So I consulted with one of the absolutely most knowledgeable players that I know, Twisted Visage on his opinion. Here are his responses on how to make Illusion changed up for doms:
[Tell] -->Twisted Visage: Thanks! Another question: what changes would make to Illusion to balance out to be usable for a dom primary?
[Tell] Twisted Visage: less temporary damage, make the AoE hold have -resist, have the phantom army use powers from the attached assault set instead of the basics for variety and utility
[Tell] -->Twisted Visage: What about PA's taunt?
[Tell] Twisted Visage: and/or make enemies that are feared take psi dmg over time if within a certain range
[Tell] Twisted Visage: I'd leave it. Taunt is handy and controlly
[Tell] Twisted Visage: tankers are essentially pbaoe controllers
[Tell] Twisted Visage: so there's a good crossover there that makes illusion feel niche
[Tell] Twisted Visage: if I were to redesign the set I'd make phantasm into a translucent version of the peacebringer tank form and call it a phantasmal killer
[Tell] -->Twisted Visage: Or call it apparition
[Tell] Twisted Visage: have it be ground based instead of flight, and have it work like a soldier mm brute pet
[Tell] Twisted Visage: with SS stomp and ko blow, etc
[Tell] -->Twisted Visage: FYI I'm posting this on the forums.
[Tell] Twisted Visage: a mixture of some of these suggestions (perhaps not all of them) would lend to make dom illusion 'feel' different than it does on control
[Tell] Twisted Visage: could be fun to call it nightmare control
[Tell] Twisted Visage: go with a dark theme
[Tell] Twisted Visage: instead of phantom army, it's Doppelgangers
[Tell] Twisted Visage: instead of Phantasm, it's Phantasmal Killer
[Tell] Twisted Visage: Instead of Spectral Terror it's Cloak of Nightmares (PBAoE toggle fear, with -res and possibly psi dot over time, like World of Confusion but with fear)
[Tell] -->Twisted Visage: OOOH I like that!
[Tell] Twisted Visage: instead of Spectral Wounds it's Waking Trauma or something, could make it a single target sleep mez like in the Mind Set, but that deals damage that is partially imaginary
[Tell] Twisted Visage: It'll have the same 'feel' as illusion, but feel more villainous and allow for dream-based heroes and villains