Hi! I just read through your post and I do have one question! Do you know that Hashirama's Ninja God talent raises Ninjutsu by 30% only? Chojuro's main damage is Taijutsu.
In arena, buffs are very important as it stacks, however, stacking various different buffs instead of stacking the buff a ninja need can reduce the effectiveness. For example, ninjutsu isn't very useful for Chojuro, so giving him a 30% Ninjutsu boost won't do much. Which effectively means that you only really have two buffs on Chojuro, which in the case of Arena, is not always enough.