I suspect that illusions are one of the sacred cows that have been killed.
Oh sure, I expect something to be brought back with the name 'Illusionist' attached to it, but I think flexible powers requiring interpretation are largely a thing of the past. I don't think you are going to see, "Make an image of whatever you want, and then figure out what it does or how the monster reacts to it." It might be at most "Make an image of whatever you want, and then whatever you make this happens."
Expect future illusions to do very specific things and have very specific effects. 'Mirror Image' is a good example of what future illusions are likely to be like:
Mirror Image Wizard Utility 10
Three duplicate images of you appear, imitating your actions perfectly and confusing your enemies.
Daily * Arcane, Illusion
Minor Action Personal
Effect: Three duplicate images of yourself appear in your space, and you gain a +6 power bonus to AC. Each time an attack misses you, one of your duplicate images disappears and the bonus granted by this power decreases by 2. When the bonus reaches 0, all your images are gone and the power ends. Otherwise, the effect lasts for 1 hour.
Illusion based attacks probably attack the Will or alternately the target's Perception score (which would be semi-cool, but largely irrelevant since both will be about the same number). Some examples:
'Phantom terrain' : treat terrain in the area of effect as difficult, ongoing, save ends
'Hypnotic Pattern' : target is immobile, ongoing, save ends
Alternating you might see some summoning type powers:
'Phantom Minion': Create a basic minion soldier whose level is equal to your level. Spend your actions to move and direct it.