The only problem I'm seeing a a first glance is that charm/dominate is going to be "frustratingly random" rather than just "difficult but worth it" if you don't have some sort of option to reduced cohesion damage from spells either by using a smaller number/die or by flat-out being able to say " I'm tempering this spell so it can't drop them below 1." Perhaps, just as a random idea, a combination where you if you drop your damage enough you ALSO get the "no KO guarantee"?

Also, now that I think of it, do the cohesion maximums on targeting apply only at the time of being targeted or does an arcanist who recovers investment after being ensorcelled into thinking he is a baboon for a turn or two suddenly snap out of it?