[brombur]

So I didn't see any restriction noted about spells that have sustain limits, ie Control actions/Thoughts. Could a mage use quickening on those sustain spells and create an army of permanently enslaved zombies? what about mob thoughts?

[Lormyr]

Yes, but the spell could eventually wear off as you continue to give the enslaved new commands to follow if the force of the spell is not sufficient to reduce their follow up resistance rolls to zero dice.

Dispelling is also a likely outcome to that endeavor at some point.

[Mirikon]

Also, those kinds of things are stuff that makes people skip other mages and go out of their way to geek you first.