they arent really all that stronger. Naruto nine tails only really makes sense with kabuto bc he cause naruto to boost his attack. Gaara is a OK tank but the thing it that you can just debuff him and focus on the character that can be comboed on and gaara will just wither with out much consequence. Same with Iruka. With tanks like those you dont want to focus your attacks on them if they can do much to u dmg wise. the best offense and defense is getting rid of ppls way of damaging you. If you look at it like the the characters get less broken. the other character that is broken rn is Tobi, but he is getting nerfed soon.

I wouldnt worry much your only on 35, theres only so far that ull be able to go in arena. Im at 62 with 750 points and I'm just now winning consistently. Worry about getting more characters and getting more power arena will be easy once you are more set with a lineup