He’s silly in ROTS once he whips out his laser dildo and goes full Henrietta. Before that point, he’s very good; I’ll go so far to say he’s better in most of the PT than he is throughout ROTJ.
I’m not familiar with that expression… Is it an obscure reference to Evil Dead II, or am I way off?
Regarding the casting of the emperor, I much prefer the calm, eerie portrayal of the original. Already in ROTJ, I thought McDiarmid’s cackling was a bit over-the-top, nevermind in ROTS. But then many things are over-the-top in ROTJ, so I guess a Revill-style emperor may not have worked as well without also darkening the tone elsewhere in the film. But I can accept that from a continuity point of view, the recasting in ESB makes sense in principle. It’s a shame they messed around with the make-up, hood and dialogue.