Or more accurately Ice Shit.
Now I know nobody really cares about it cause its very rare blah blah blah.
But this card is THE WORST CARD in the whole of TFW.
It is seriously blatantly useless. And I even have a whole deck dedicating to making it DO something... anything.

Even with various ways to move it around, any other enchantment is just plain better, sadly even things totally unrelated to it

Before you suggest to move it so it displaces a building clipping a well know that theres 50% chance of actually moving it closer to the well. And you need another SPECIALIZED card to do it. And you'd be better of with steam vent, wandering whorl or alp.

Seriously ive played about 20 games with the darn thing in a tailored deck where everything is trying to help it, hoping to do anything with it that will have ANY impact on ANY situation. And im not talking something awesome, just getting it to be on a level of ie. Micro tectonics.
Closest analogue would be the dwarven thing that plops a mountain and moves[Uplifted earth], or elemental "switch a hex place" [Micro tectonics] (sorry about the names. EDIT-added)

This card could use an option to cast on an occupied hex but cost +2flux if its a building.
Or do something like turn a water hex into a plains (simulating the water freezing).
Maybe rethink it completely, make it something different.
Or something... anything. Cause you might have as well just wasted its artwork the way it is now.

Here's simple examples: negate Rune of Swiftness near enemy base, use for Gossamer Palace (it cost 0), negate Steam Vent if you want to attack from that space.
With Flash Flood or Island Banishment you can sink enemy creature. And this is non-random usage that always works.
Or just a chance to move creature into water, away from Emerald spring, undimmed Mosslight Slor and so on.

Still not enough?

Man it really shows you havent actually played with it.
None of those things you said are viable in actual play. Except for Rune and i guess Gossamer palace, but there are a gazilion other land enchants that work with it.

Biggest problem is that Ice Sheet CANNOT BE CAST ON A SPACE THAT IS OCCUPIED, and moving it with other cards (which are at best situational on their own) costs flux and 2card combo.
Sure with a lot of other cards it can be made into a situationaly "heh nice, but whatever".

Look im not gonna bother, but the card really is useless.
Seriously ive seen decompose(grow a forest from a corpse) have a greater effect on the game.

My last suggestion is to rethink the card in some way.

-How about an inverse of Flash flood, temporarily making all unoccupied water into plains. Its an unwanted effect for elementals (but odd cards are usually counter culture). But it has a counterpart, easy peasy to code and is quite fluffy, heh, makes one think of d-day landing A nice suprise occasionally, and welcomed in a multi-domain dwarf deck.

Try to place it on hex opponent spawns his creatures on. Especially if there's water next to it..
If you want to make a combo, place Steam Vent on next hex (best is on adjacent spawn point) - works really well

Or if there's a bridge over water, Uplift the Earth (unless there already are mountains) - and put the Sheet there .. also nice chance for any creature to fall into water =)

It might be good in some very flux-expensive deck, like with lesser anemois, to get maximum use out of your draws (not having to cycle anything because of flux-shortage), but then again sheet is very situational and will clog your hand quite badly until there is a moment to get some use from it. It just takes valuable hand-space, and even worse if you try to combo it with something.

It only affects land spaces currently, right? How about making it possible to cast on ocean too with a different effect: "If Ice Sheet is on ocean, aquatic figures in this space have their speed reduced to 0 and any figures in this space can be meleed as though they were on land"? The original ability of moving figures would have to be modified: "If ice sheet is on land, figure in this space is moved to random adjacent space".

EDIT: To make it clear, it would behave like it does now on land spaces, but wouldn't have the "moved to random adjacent space" effect on ocean, and instead this different ability. When on ocean, it would for example make a grounded aloft or swimming creature possible to melee with a land creature.

I guess the simplest and possibly best solution for this sad card is for it to lose the "Figure" part (change to creatures only) and the "Unoccupied" part.

So it would be castable on occupyied hexes but would only move creatures.

And before somebody goes "But then you have a chance to push a creature into the water!!"...
for 1 more flux just use cloudburst (and its still more usefull to use it).