I know you said one thing, but...

I would want them to stop developing stupid therapist voices. Talk like a normal person ffs.

Also, stop with all the lies about being superhuman in their ability to withhold judgement. They judge clients all the damn time and they're only marginally better at hiding it.

Related to the first point, also no more making weird faces at the client and doing manipulative/bizarre mirroring.

Those would be my preferences.

ETA: Also, their missteps should be referred to as "acting out."