That got me wondering how most people prefer to play Conjurers. I have no idea, I've never played one, so this poll is research for me. In my mind, I think it would be fun to have a Wizard's Duel over who has control. If the enemy summons a spider to kill you, wouldn't you at least like to TRY to snatch control of that spider and turn it against him? That sounds wildly exciting! So why wouldn't they also do it to you?
And I wondered, what your own Summoned monsters found a way to break your control and you had to do something to regain it? I don't mean just simply re-casting the spell, but I mean like some mouse-click combo merged with a RPG check against your Control skill and if you win, they are yours again. If not, they are now your newest enemy, and hate you twice over what any normal version of that monster would, since you formerly enslaved them. They might go BEZERK on you at this point!
It could add some spice to the Class of Conjurer and throw some instability into the mix. I don't think magic is entirely reliable, it's usually an unstable force, often dropping out on your when you need it most. Just some thoughts.