Plaguebringer illusion is only one I am aware of that has mana regen. Every other illusion has AC which is quite the bummer. Granted you can always buff block the bonus effect of an illusion and buff block the illusion component of plaguebringer... therefore giving you the cool illusion and the bonus mana regen. Having said that, it sure would be nice for INT casters, or WIS casters not caring about AC, to have some more mana regen (or other stat effect) illusions on SC. Maybe some caster like illusions with robes and such would be cool and stuff...
I don't think you can block the illusion of the plaguebringer, at least I couldn't during VoA. When I blocked it, I didn't get the mana regen part of it either on my alt.
Yeah would be nice if you didn't have to click off other illusions to get the secondary benefit from the clicks. And agree would love some more with effects other than AC, especially considering the AC is the same on all of them so you are just buying them for the illusion. Would love another one with mana regen on it that did not include a damage shield so I can remove ranger ac/ds buff from my already full blocked spells. Even something like a small amount of spell damage and heal amount would be nice. If you are afraid that they won't sell as well because the melee and tanks won't want them just make 2 illusions, one with AC as the bonus and one with bonus that casters would like.