D&D 4E Illlusion projection powers in 4e (Dead Gods conversiion)

[Felon]

I'm currently running the 2e Planescape adventure Dead Gods. One of the challenges of converting it is trying to bring the visages' power of "lucidity control" in line with 4e rules, which don't provide much of a basis for powers with long durations and widely open-ended effects on the target.

Here's the description of the ability from Dead Gods:

First and foremost, a visage wields a strange power that graybeards call lucidity control. The fiend can reach into the mind of anyone it sees and change how he perceives the world around him. The visage totally controls the victim’s senses, but it usually does so in subtle ways so the sod won’t realize that he’s being manipulated. As long as the victim is unaware of the visage’s assault, he receives no saving throw against the effect. However, if he tumbles to the fact that something’s playing with his mind, he can attempt a saving throw versus spell. Success indicates that the victim perceives things as they truly are, but he must continue to make successful saving throws each round or fall back into the false reality created by the visage.

To make it less likely that a sod‘ll realize his perceptions are being orchestrated, the undead fiends often mix real experiences with false ones. For example, a visage might artificially exaggerate perceived distances, make real objects appear to fall or move at inopporlune times, change the way a building seems to be laid out, and so on.

The thing to remember is that a visage loves to cause confusion and fear. Sure, it could shut off a berk‘s senses entirely, but it‘d much rather do something disorienting and strange. Then, when a victim can no longer trust his own eyes and em, the fiend rakes with its claws or simply manipulates the sod toward a homble end (maneuvering him into a pit, stining up another creature to attack him, and so on).

As you can see, the illusion can impose a number of conditions--for starters, it can immobilize, blind/grant concealment, and even cause someone to attack another character. That opens the possibility of simply making a bunch of attacks with the "illusion" keyword that inflict different conditions. That would make a pretty vanilla controller monster, but right now I'm trying to use the "hallucinatory" rituals from the PHB as the basis for this ability so it will stay open-ended. To do so, I've got to work the Insight skill in there as a defense, probably by having the visage make an Arcana or Bluff check against passive Insight. I also have to decide if saving throws will come into play at all, or if the illusion's duration is simply a matter of sustained actions and successful checks verus Insight.

Another consideration is that, unlike the rituals, these illusions are not disrupted easily; I have to figure out what happens if the illusion attacks the character, as well as what happens if the character is physically attacked by something concealed by the illusion.

Yest anotehr possibility is to make lucidity control into a combat skill challenge.

Anyone else been mulling over illusion powers? Sometimes I feel like I'm missing some solutions that are staring me in the face.