Why?: Because there is no real strategy behind that team. Is annoying totally op (i see it in arena(even in practice section, like really?? what do you have to practice with that team), i see the same formation in convoy and plunder, even in great ninja war. Another reason nerf it is because the mystery of tenten use all chakra nature plus a critical buff, and every ninja has percentge of weaknes of -20% of weakness of one element., soo take a hit of that in first turn is brutal. One more thing is that the strategy to beat that consist of how quick you kill mabui(including the water main clone in front of her) or how much resistance you have to take or heal that damage, but lets be honest by the 3rd turn mabui doesnt matter anymore if you still alive by with at least 2 ninjas.

How nerf it?? is really easy actually you reduce mabui increase of chakra that it doesnt reach 60 first turn or just increse the cooldown of tenten that her mystery can be activated in the second turn. At least that way the oponent has a chance to deal with it.

This are my thoughts so if anyone is agree or disagree with me is totally fine is just that im sick of how some players only cares about winning or just they can not feel how good this game and how good some other ninjas are and dont even try to experiment with them, because some playeres use that formation all the time to everything even for ninja exam, ninja exam is something where you can improve your skills and other ninjas, also is the perfect place to test new strategies and not the same thing over and over again.