This. Illusion magic has always sat very closely to charm / compulsion magic, from a concept / fluff standpoint.
Patterns and Phantasms sat closely to Enchantment.
Figments and Glamars were image effects that did not affect the mind at all and could be seen by everyone. No mind affecting.
Shadow illusions was weak version of reality. No mind affecting.
Most people have no problem wrapping their heads around the idea of mental compulsions causing foes to behave in ways they wouldn't. It just takes a bit of a leap to say the same for illusions. For me, it's enough to say "it's magic!". But really there's plenty of examples in folklore of protagonists not heading danger to chase after "the shiny" (Will-o-wisps, leprechaun gold etc.). If it's still problematic I would say add the charm keyword to all illusions and be done with it. It likely wouldn't cause any balance issues.
In general I prefer this approach over having half the creatures in the MM being immune to mind affecting / illusion spells.
I would have no problem with this either if that were the rule.
It isn't.
I really think that the designers could have sat down and carefully figured this type of thing out.
If they wanted illusions to be compulsion, fine. Do so. Protections vs. mind affects would then apply.
But they already have a Charm effect for that. So, why is an Illusion like Visions of Avarice doing a Charm effect without the Charm keyword?
The Illusions section of Arcane Power claims that it affects the foe's mind, but then there are no game mechanics for protecting against that.
Disguise Self is an illusion, but it appears to be a Figment or Glamer, not an Arcane Power mind affecting illusion.
The Monster Manual has immune to illusion monsters. Does that mean that the monsters are immune to the entire power, or are they still affected by psychic damage? Presumably, Psychic is not the same as Illusion. But, what part of a power is illusion and what part is psychic. Is psychic just the damage part and other conditions are illusion? Who knows? There are no set rules TMK.
How about the Insight skill (sensing an illusion) versus a mental illusion like Visions of Avarice? Where are the rules on this?
But from what I can tell for Arcane Power, they sort of, kind of, pulled the 3.5 Enchantment school of magic into the 3.5 Illusion school of magic (mostly Pattern / Phantasm) and then threw out some portion of the 3.5 Illusion school of magic (Figments / Glamers, and Shadowmagic, not completely, but partially) and then said "Done" without figuring out how that affects the rest of the game system.
They didn't even bother to compare Players Handbook Illusion magic with Arcane Power Illusion magic.
The former is Figment / Glamer type illusions and the latter is Patterns / Phantasms. How do they interact? Nobody knows.
It's a bit jarring and pretty lame that they didn't take the time out to come up with a clean comprehensive system. IMO. They ignored the Charm and Illusion keywords in the PHB and made up a new combined Charm/Illusion keyword called Illusion. But Illusion in Arcane Power is not the same as the Illusion keyword in the PHB.
Yup. A DM can make up his own rules on it. A DM can ignore it all (no charm in the illusion spell = no bonus to saves for an Eladrin).
I just think they dropped the ball big time. This could have been handled so much cleaner.