Oh wow. I don't even know. I have to type my thoughts out here, sorry if I offend anyone with my opinions on these characters.
Kuma. He's got a weird design that just doesn't sit right with me. Not bad, but it just always looked awkward. His ability is cool, but somehow it seems too h4x to ever be seen in a real fight. But to add on to that, he lacks anything resembling a personality, even before he went full cyborg. You never go full cyborg, man. He is still kinda shrouded in mystery. Having him be with Dragon during Luffy's flashback felt entirely tacked on. He did some things with good intentions in mind for the Straw Hats, which is nice. But even then, he's just so unbelievably boring to me, and I wouldn't care if Oda completely forgot about him because I likely will have forgotten about him too. How he coulda been made more interesting? Make him an intimidating opponent from when he appeared at Thriller Bark. None of that cyborg or revolutionary stuff. Or if the revolutionary stuff is necessary, then make it feel less forced.
Kizaru. To me he's just "some marine guy". His introduction was too over-the-top for me to take him seriously, and I have never enjoyed him in any of his appearances. His abilities are pure h4x and he could prolly destroy any character in the series if he wanted to. He should have owned in the war, yet he didn't. Just seems like an overrated character.
So, I guess I just don't like either of them. No vote from me.