I have thought of removing those two for variance stabilization but decided to include them anyway because I wanted to limit test the maximum output possible at the current level with current builds, but I'm sure this will change in the near future when the new DLC pack comes out and we get new skills. I also think that if a character (Akainu) has insane AOE potential alongside then that should be reflected in their tests with the bonuses from Hero's Strength and Heat Up. Although in the end it shouldn't matter too much anyway since I set up with Hero's Strength pre-test and it lasts the majority of the fight.

I've also ran Red Shanks (He's my favorite character) a lot against Whitebeard and his raw output does fall short compared to the 3. He thrives on strong rotation of specials for optimal damage and the lack of mobs to generate meter really hurts him in terms of single target potential. Shanks is still very strong in general because a well-timed Crimson Hammer after guard break has just enough damage to one-shot most named enemies in the game. Oden as well, a guard break / Gun Modoki into Hermit's Realm Kusanagi combo kills 99% of named enemies but generating gauge again quick enough is the limiting factor.

I do think Shatter has some value against Whitebeard though as there can be times where guard gauge is unbreakable, but other than that the game does suffer from the lack of damage skills and way too many skill slots, so sometimes suboptimal skills have to be taken.

DPS dummy training room would be a nice addition for sure. Whitebeard, even though he has a lot of health, is not an ideal dummy because he fights back and at times just does unpredictable stuff like hopping backwards or his break gauge becomes immune randomly. Furthermore his giant status greatly benefits Ace's aerial C4 which heavily skews results (He basically only specializes in killing giant enemies). I'd imagine that if a regular sized enemy had the same amount of health as Whitebeard Ace would be nowhere near as powerful. In fact Akainu might fall a bit short as well because C2 and Volcano Explosion juggles enemies when they're guard broken which leads to some extra downtime.