Here's my initial opinion on the new Sylvan cards. I've got to say, overall I'm a bit disappointed with them.

Buildings

Kithil'aa Treehouse
3SSX Rare
Aloft
Is destoyed if not in forest at the end of the round.
Spawn in forest
0A 4H 0S 3V 0R

3 vision with Aloft makes for a very good building. It's strength is nicely balanced with the need to spawn in a forest. I like this one.

Buildings/Creatures

Long Root Elm
2SX Rare
Treent
(Long Root Elm is a Building and a Creature)
Spawn Forest
1A 5H 0S 1V 0R

Long Root Elm is probably the most interesting card that Sylvan gets. It's pretty neat to make a building and then Teleport it somewhere. PUtting it by Emerald Spring is also fun. I don't know how useful this card will actually turn out to be, but I think it is a good addition to the game.

Creatures

Arendor Treefolk
2SX Common
Treent
Forestride
Is destroyed if not in forest at the end of the round.
Seedling Corpse.
Spawn in Forest.
2A 3H 3S 3V 0R

I do not like this card at all. It's weak, and it's boring. The drawback is harsh and doesn't make sense thematically. I think the card should be reworked somehow. My suggestion:
Arendor Treefolk
2SX Common
Treent
Forestride
All friendly creatures in contiguous forest gets +1 Max Health
Seedling Corpse.
Spawn in Forest.
2A 1H 3S 3V 0R

Mosslight Griffin
3SX Uncommon
Aloft
2A 2H 3S 3V 0R

This is a solid card. The only thing I dislike is the fact that it's identical to Sky Cavalier. This ruins the uniqueness of the card. Either this card or Sky Cavalier should be tweaked a little.

Kodiak
4SX Uncommon
Beast
Forestride
2A 5H 4S 3V 0R

This is another solid, if unexciting, card.

Illyrion Lancer
5SX Common
Centaur
2A 3H 7S 4V 0R

This should definitely only cost 5S. It's right at the power level of Lesser Anemoi, Seething Archosaur, and Apprentice Timesap. At two domain, it's pretty junky.

Twinling
1SXX Odd
Elf
Comes into play as two separate Twinlings both must be played by your base. If either is removed or destroyed so is the other.
1A 2H 4S 4V 0R

In general, I think that the 3 domain, 1 flux creatures are a bit too weak. If it stays at 1SXX, either the last sentence needs to be removed, or it needs 2 attack.

Enchantments

Covert Mission
2S Common
Enchant Creature
Creature gains -1 attack, +2 speed, +1 Vision.

Compared to Hide to Horns, it offers less benefit for you and less detriment to your opponent. This should cost 1S.

Kudzu
1SX Common
Enchant Forest
1,(Dim): Land space adjacent to this contiguous Forest becomes a Forest.

This is good at what it does. It's a little lackluster compared to Arid Encroachment, but making Forests is much more impacting than making Deserts. It's just fine.

Knight of Celador
2SX Rare
Enchant Creature
Enchanted Creature becomes a Knight. If this Creature can see two other friendly creatures it gives you control of all spaces within 1.

I really like all the additions of non-building ways to gain control. This is the cheapest option, and probably the most difficult to use. It's a nice addition to the Sylvan army.

Benefits of Numbers
3SX Uncommon
Enchant World
Whoever has the most creatures at the end of the round gains a glory.

I like this card. Giving creature decks ways to gain glory without having to capture flux wells is good. Compared to Benefits of Spectacle, it's more likely to backfire on you, but it costs more to play. I think this can use a 1 flux reduction to cost 2SX.

Lycanthropy, Bear
2SXX Uncommon
Enchant Your Creature
Lycanthropy, Bear starts with a Taken Kodiak.
1: This Creatue is taken and previously taken Creature is returned here. This enchantment now Enchants the returned creature.

I like the idea of this card, but not necessarily the execution. It pretty much plays as a Kodiak that costs 3SXX instead of 4SX or a 3SXX Morph that can target only Kodiak. Right now, I don't think it's very good, but future cards that trigger when a creature enters play can increase the usefulness of this card.

Spells

Recall
1S Uncommon
Target creature is moved next to the nearest base of its domain.

It's a very limited Teleport. You get what you pay for.

Silviculture
3SX Common
Target land space and all adjacent land spaces become forest.

It has to compete with Naturescaping, Wider Woods, and now Kudzu for forest creation. While not bad, it's not as good as any of those. I really, really want this to only cost 3S. That way people might play it with Treetop Dominion for some Sylvan domain acceleration.

Overall, I'm not too impressed by the new Sylvan additions. Arendor Treefolk, Illyrion Lancer, Twinling, Covert Mission, Benefits of Numbers, and Silviculture could all stand a boost of some sort, and Mosslight Griffin is a carbon copy of creature. They got no new 1 domain creatures, no ways to deal with buildings, and no new creatures with more than 2 attack. The latter two are further impacted by the loss of Bear Strength. Buildings and Creatures with Armor are going to be a bigger pain for Sylvan than before.

Little comment about this card: you say that it is too cheap, but look at most MF creatures like Crushing Wheel, Glorn Airship and War Blimp. Or at least Epic Veteran and Hadth, Drill Sergeant. :/

Just noticed something with "Recall".
What if there's no base of the same domain?

Spell Canceled?

I thought the same after seeing them and even after trying them out. And Lancer is actually much weaker than Archosaur in my opinion. Archosaur doesnt really lose much to it in mobility thanks to swampstride and swimming, but the croc's special ability is a killer.

I think you aren't that impressed with the new sylvan cards because you haven't had a chance to really play with them. They require new strats besides just weenie rush now. I think the new set makes them even stronger than they were pre-ascent change.

Long root is fantastic and combos great with other cards.

Lancer is better than you give him credit for. 7 speed and 2 attack is enough to terrorize quite effectively.

Treefolk seems a bit weak, but if you're going forest-creation then he's fine (super home guard, but better) he's not the best card on the planet, but they all can't be.

twinling, I'm not sure what the appeal is, even in a benefit of numbers deck, it still takes a while to get them out.

Yes, 7 speed with 2 attack is good, but is it worth 5SX? Especially when it only has 3 health. I think it can be compared to Goose Tamer: I think that Illyrion Lancer's 7 speed gives it the edge over Goose Tamer in mobility, just barely. The extra vision also helps. However, the extra health Goose Tamer has is huge. Also, Goose Tamer can attack aquatic creatures. All in all, I think that the creatures are about on par on terms of power. With that said, I can't bring myself to pay an extra flux for Illyrion Lancer when I can easily play with a similarly-powered creature that serves a similar role for cheaper.

I disagree with you that Arendor Treefolk is fine in a forest-creation deck. Sure, with forests everywhere he can compete with similar creatures, like Panther Disciple, but if I go through all the trouble of making forests, I want to be rewarded for playing my forest-bound creature. What if he had an extra attack? Sylvan are lacking in the 3 attack department, and being so forest-bound, I can't convince myself that he'd be too strong.

On Covert Mission - I actually do like cards that increase speed, like Sparrow Scouts and Tailwinds. Yes, Covert Mission can be useful by increasing the speed of slow creatures. But is it worth the cost in flux to do so? Playing with the big slowpokes, I'd rather play Sparrow Scouts instead of Covert Mission the vast majority of the time. Yeah, that creature isn't quite as fast, but if I have even one additional creature out I'm getting a good benefit. Plus, if that creature dies, the next one will be faster also. If I want a faster, weaker, and more expensive Hadth, Drill Sergeant, I'd just play with Sadathian Mercenaries and save a card and a flux.

On a more positive note, Long Root Elm really is a wonderful card. It's unique and open-ended in the ways to play it. I foresee many creative decks using these.

So far in the domain league I would have to agree about some of these creatures.

I'd make the Arendson Treefolk bigger and give them either forest teleport or forest creation (compare to either the Dust Devil or the Swamp Thing (chaos swamp beast)). Actually, if the ability 1-teleport to target forest was added, it would be great.

Lancer really should be 1 domain and would still be weaker than the Archosaur and arguably the Time Sap. He's amazing against the computer when he can hit, run, heal and repeat, but human opponents are too aggresive for that and overpower him before his speed can be that much of a factor. Maybe if the map were 50% larger he would be worth it....alternately, cuting his cost to 4 would help but I think Goose Tamer would still be better.

Griffin went up 1 flux cost for more speed and vision. I think it was slightly stronger before, but still good.

Silviculture at 2S seems like it may have some potential with Treetop Dominion. Pretty unreliable with only 1 of each though. Kudzu gets expensive to run quickly. Not sure what the answer is there, but it seems with more cards manipulating terrain that forests need to be as easy to create as they are to destroy. I think Silviculture may actually be the better option now.

Covert Mission might be usable in combined S/MF, but Sylvan creatures are already high speed, high vision, low attack (and low health). It takes most Sylvan creatures from 2 attack to 1 or 1 to 0 which makes it basically horns to hide without the hide.

Unfortunately, it seems I got all the new Sylvan cards people don't like and none of the ones people like in my first domain pack. Hopefully the next will go better.

Well, now after some nerfs and Griffin changing, I'm starting to think the new sylvan stuff is quite alright. Only lancer and Areandor might deserve some small buffs in my opinion.

I think griffin is actually better now, even better than Goose Tamer. The only drawback, 2 health matters mostly only against brimstone powder, volcano and cull the weak. Aloft protects the guy from a lot of harm, allows attacks from water and flying over things, which goose can't do, and 4 vision is awesome.

Jed really owned me in brass today with a Blimp enchanted with covert mission. True, not so great in mono sylvan, but sylvan still has a lot of powerhouse commons for limited play, so I don't see a problem with this.

And nighthawk, correct me if I'm wrong, but I recall you got a Kithil Treehouse in that domain? That's an awesome card, one of the best buildings I would say, and will be worth some 300 gold later. And you did get at least one awesome griffin and some always good slors and emerald springs, eh?

Nighthawk; just imagine - enemy, unaware of your evilness, puts his first base on forest, and it turns out there are also other forests adjacent.
Fine, he knows - you play sylvan, watch out for treents .. but these usually are easy to deal with, so they're pretty much neglected, leaving no watch right next to his base.
Then you play Treefolk.. it's really big pain to deal with it. Buys you lot of turns when he is stuck next to his base.. and then.. when he FINALLY gets rid of it... you just cast another one.
Believe me, this has lost me a domain game and won me Keep Cards game (ask jed).. these are really great

Griffin is great also, I'd rather have this one than Goose. Advantages were already pointed out by headshot. (+imagine him with that Cover Mission and Knight of Celador - gives you control of whole map [damn. shouldnt've said this!])

Lancer rocks on every other map than these flat ones. Ability to run throught two mountains and still hit afterwards make him really good I think. +he can shoot

Silviculture is I think even better then Naturescaping.. just drowns 7 hexes into forest - deep forest, Wilds, Treefolks and many other uses...

Treehouse is awesome, but I don't think I can actually attribute any games to it. The game was pretty well decided one way or the other most of the time it came into play. The one time it might have given me the game, it was destroyed by a 3 damage, 4 range Twisted Nomad from the edge of the board. In spite of vision 3, think in most situations it is a worse play than Loyal Wilds....but Loyal Wilds is very good.

(Treehouse prices are currently 150 bid, 250 ask on the market, no sales yet...the other 2 rares I got combine for less than half that).

I do like the Griffin and on reflection he may be better than the Sky Cav, even with the extra cost. However, the idea that if you throw 2 enchants on him he's great also just makes him a huge target for Lysis, Creeping Doom, Volcano, Ascent, etc, etc. Beyond that, one of the enchants you mention is clearly a very strong card, but also a rare that few have yet.

Arendor Treefolk is cheap at 2 flux, but that is about all it has going for it. Compare to the unspectacular but solid Axe Captain for 3 flux. Rebellious Serfs outclass both of them as for 3 flux they can spawn right on the enemy base regardless of terrain and have no drawbacks.
Twisted Nomad at 2 flux sometimes is useless but other times is an absolute beast. Dust Devil has similar drawbacks and for 3 flux gets +2 attack, +2 health, and the ability to teleport. While efficient, the treefolk is unreliable without the benefit of also being able to be spectacular.

Lancer is fast, but generally has to either avoid a fight or lose flux for flux. Mauler 1-shots him and has half its life left. Archosaur at 1 domain cannot be killed by a Lancer without the opportunity to kill the Lancer back. Outside of the flats, Goose Tamer is often faster. However, Lancer's ability to shoot is useful in quite a few situations: Hadarck's Fort, Treehouse, Thunderhead Reach, boats on single water spaces (although they're likely to get a free shot at you), move next to a flyer and if they don't move you can shoot them the following turn, finish off Entangled targets. A quick harasser can be nice, but only if you have a regular army to back him up.

Twinling is extremely underwhelming compared to the other 3 domain creatures in the set.

I think my army would be much better balanced with a Kodiak or Pine Ent or something else that can stand its ground and fight rather than being forced to evade or die. That may be more a factor of the cards I got than Sylvan as a whole though. I have made some modifications that I think make my army better...but unfortunately I'm out of games and there doesn't seem to be a way to practice domain except against the computer.