Ok so at worst, Kizaru got great speed feats (and defensive feats), arguably cementing him at #1 in that category. This can't be seen as anything else than a W, the size of the W can be debated for him.
I guess it does come off overhyped now if we made it sound like Kizaru trashed advCoC Luffy, we don't have a clear cut answer for why Oda insists on avoiding CoC use, but it's either.
1.because he wanted Kizaru to trash Luffy first. And if AdvCoC was used that can't happen.
2.because Luffy needs to figure out how to land attacks on Kizaru first, and using advCoC/wasting haki is useless atm.
Note, if it's #2 this is like claiming Katakuri only fought fishman island level Luffy the entire fight, ignoring the fact that Luffy using his strongest form was useless against Katakuri and would lead to his defeat faster.