I have Luffy beating Kuzan based on his Hachinosu showings, they aren't enough to defeat top tiers. Much as it sucks to admit it, his df is looking useless.
Kizaru as he currently is, is already a nightmare for most top tiers. Kuzan absolutely needs to have something else, i.e an awakening. I think that's how he will end up matching someone like Kizaru, with a ridiculous awakening, where his ice based abilities are actually lethal against top tiers.
Throwing telegraphed punches, sorry that ain't cutting it against Kizaru.