I like Illusory Wall and Maze of Mirrors. Conceptually I like Phantasmal Terrain and Enemies Abound, but I have mechanical nitpicks with both - if Phantasmal Terrain is illusory, why isn't there any ability to disbelieve it? And Enemies Abound gives flanking, but the target still attacks you and not his allies? Er, wha? I can only figure the level they picked didn't warrant the effect, but the fluff and the mechanics just don't reconcile at all for me.
I'm also mildly disappointed that a few of them, particularly Illusory Ambush, just feel like generic spells with some illusion fluff slapped on them. But then I dunno what I'd do to fix it either. I'm not sure that it's really any worse than the shadow conjurations of 3e, it just feels different for some reason I can't really put my finger on.
So, any thoughts on how to do permanent illusions? On the one hand, that pretty much screams ritual to me. On the other, I consider illusionist to be a pretty distinct archetype, and that to me should be within the illusionist's purview and not something anyone can pick up.