Taj was just so awesome he made Mewtwo look like a good character :D Mewtwo had a few good points like his tilits and great wavedash but there were so many things against him
He was a huge target, He was slow AND lightwieght (really bad combination), Again huge hurtbox, Bad match-ups, Down smash only hit one side, Lack of defense options, He was HUGE, Highest crouch in the game, Easy to KO, Bad spotdodge
...and so on. Oh, and did I mention he was HUGE?
But I absolutely refuse to believe he was worse than Pichu >.<