In all fairness Christopher Lee wasn't really given much to work with. Lucas could have kept the mystery of whose side he was really on in Episode II for more than 30 seconds, maybe even not reveal his true allegiance until the third film. They also killed him off way too early in ROTS.
His old pal Peter Cushing, (also a Hammer vet) had enough on the script page to make Tarkin memorable.
Not keeping Dooku around to exchange curious glances with a younger Tarkin was an missed opportunity! And if Clone Wars does it, I'll faint from shock. I'm still amazed they've made Anakin and Padme into better characters. ;)