I don't think Zidane's Trance was awesome merely for the sake of getting rid of crappy Skills. Remember, he is the new angel of death? The destroyer of Gaia? Kuja was badass enough, but when he went Trance he destroyed one world and nearly destroyed another. It makes sense that his replacement would be equally, if not more awesome (don't see Kuja hitting any 9999s! Sucka!).