we havent seen grevious completely. from what i saw inthe cartoon thou he seems very cool. he has a persona we havent seen b4. a supert warrier that goes and kill the enemy captains himself.have you notices how most of the villians in SW dont do things like this papi stays int he shadows as the sith lord until he knows that it is perfectly safe to come out. vader is cool and decided not blood thirsty. same with tarkin, dooku is just and idoit. and maul is all attack no talk. that is what set gevious aside. he has the best of both worlds.