The problem is not naruto but the lack of initiative imho.

Personally speaking i tend to test a lot of for fun ninja lineups in arena and most of the times i win (last two i tried were: shizuka 4*, kisame samehada, kurama with BD and han edo tensei, bee sst, asuma wb trialed with cf) but i have to admit it happens because i almost always have the upper hand in initiative in training arena against who i face.