A great idea - Christopher Lee as a rogue Jedi
Failed execution - see aboveand while talking about bad (and badly executed) freakin’ ideas:
General Greivous.
I like the idea of a Sith who is a sophisticated gentleman on the outside but inside is evil to the core; Lee played Dooku always calm and in control on the surface and I wish Lee had been given more screen time.
Greivous was very well executed in that Clone Wars microseries, but yes his conception was a silly idea. One of the prequels problems was that Lucas kept introducing a new “main” villain every movie. What would have been wrong with Darth Maul as the main antagonist for the entire PT?