I agree with you on General Grievous as long as it's in the context of the film. But in Star Wars: Clone Wars (isolated some clips in the vid to show this), he seems like a villain that very well COULD have been realized as great and memorable. The unique design of his character, his intimidating demeanor, the fluidity of which he makes his movements, all of it build up to high potential that never made it to ROTS, mainly because of the coughing/weazing/hunching of his back, etc.