Taj isn't doing anything new. Except maybe for the moonwalk stuff. But it's not enough to do new stuff either. You have to take your new techniques and develop new solid strats that yield great results.
Generally speaking when evolving the meta there are several key points you have to hit on.
New ways to approach that are safer, faster, better, more reliable and yield great results.
New combos that yield great damage or lead to death.
Better ways to apply pressure that still keep you safe.
Better ways to force a reaction and put you in a better position.
Discovering new applications of old moves or strats and reinventing those strats.
New ways to abuse moves.
More ways to take control of the match. (This is very important)
There is more, but those are the key points. Has Taj found new ways to do all that with M2 if there even are any? And can M2 do those things better then the people above him? That's another important thing to remember. It's great if a characters metagame has evolved, but is it enough that it makes that character better then the ones above him or did that character just close the gap somewhat?