I am not so sure this idea will be good PvP and balance wise. It takes out the originality from some of the classes for example Ranger and Necromancer who will have some sort of minions and pets while doing PvP or PvE. The idea for an untargetable pet who can even CC will be really broken. There should be some kind of counter play mechanic that will depend on skill and not depend on if my pet has a stun and yours doesn't or my stun is off cooldown etc etc. The idea sounds sort of fun, but it's too Pokemonish for me and it will abolish a little player skill due to the fact that you can get healed, have a free stun on a target, do damage and on top of that there is no counter play to this ? Don't get me wrong your idea could work if it's balanced a lot more, but like I said for me personally I don't seem to like it. Also the class identity will be at stake like I said at the start.
~ Yours Truly
It could be just pve pet i was just suggesting some stuff. Also nothing is yet determined since Armegon haven't said his opinion in the idea. Of course it needs a lot of polishing but it can become something really good and unique.
Regards,
Shock :)