Ah yes illusionist/trickster its all a blur to me. I wasnt clear enough
Yes this guy is key to much fun. Heck gnomes in general are. Especially combined with sylvan.
If you have good building vision (ivory towers with +7health, or oaks with gnomes), just a single illusionist will give +7attack to your bears(and more next turn) AND extra domain if using Treetop dominion. (forested mountains ftw!)
In other news, great idea with the vessel of cathill!