I suspect that stars of a ninja may very well play a role in arena fights.

As for the thing about the water main meta team as someone who uses/has used the "cancer" meta water, mei, mabui, and gnw 1010... I agree it is overused, but meh it's whatever I ignore the game half of the time anyways... hence why I run it while in arena. #AutoIsTheLife xD - I know it's weaknesses well, and could counter it well enough if I wanted too, but as stated I just ignore the game while fighting in pvp or else I'd drive myself nuts with the things I find ridiculous in games... innate advantages is no stranger to me... it is what it is, we have to accept it and move on, as some complaints will never be listened too sadly. No need to waster your breadth/time getting angry over something that is likely going to go unchanged for quite some time sadly.