Greg

The only reason black Beard managed kill white beard is because black beard waited until he was worn down from fighting. If black beard had the guts to face pops in a fair fight black beard would have been slaughtered.

Mark that's also in part of Piccolo's training. Piccolo has set the standard for: Technique beats power that is how he was able to whip Gohan into shape so quickly. Piccolo trained Gohan in both body and mind saying he needed to do more than psych himself up using emotions to fuel his urgency for strength.

If Piccolo and Gohan were to use the hyperbolic time chamber for 3 days they would reach two transformations beyond what they already have.

It depends on the individual and the devil fruit. Take Luffy for instance, gear 4 makes use of the tensile strength of rubber and increases it's tensile strength with armament haki.

As Doflamingo said: haki and rubber working as one.

Then you have Katakuri who uses foresight observation haki to see the future and shapes his body to avoid attacks.

Then there's Apoo who relies almost entirely on his devil fruit. And Caribou who has a devil fruit and no haki and wonders why he always loses.

Then you have mihawk, Shanks, Raleigh and Roger who have haki but no devil fruits, they've trained for decades and are as powerful if not more so than most devil fruit users.

It all depends on how you use haki and/or devil fruit.

You forgot ssj blue evolved that Vegeta unlocked during the t.o.p. That is essentially

ssj-blue-2. So this should either not include ssj-1 or you missed a transformation.

How can you compare Ichigo's integrity to mass murders like eren and light? Yes they both had good intentions at first but they both grow drunk on power. Ichigo gains tremendous power but never lets it go to his head. Ichigo didn't commit mass murder/genocide.

And Saitama, How many times are you going to compare gag characters to non gag characters? Saitama's power has already been stated to be comedic. Ichigo uses his overwhelming power when he needs to and not for his personal enjoyment.

Resource gathering and crafting especially for end game content. That means the ability to craft new gear and repair item durability as well as craft consumables and ammo also if the game map is massive base building.