Usyk was great Saturday. Totally enjoyed the fight. But I don't know how you can be pound-for-pound #1 when you aren't even the top guy in your division. That's why pound-for-pound was always silly to me. But go ahead and run with that.
TBH it's a deeply flawed concept to begin with. I'm baffled by how someone can compare weight-bully achievements with heavies (who don't cut at all) in the first place and feel like there's any credibility to that comparison. Having said that, it's about fighting weight and often accomplishments in multiple divisions - Fury being arguably better doesn't really affect P4P when he weighs in 40-50lbs heavier (the difference between Wilder's typical weight and a SMW like Canelo). Quite aside from which, heavyweight is essentially unlimited - in that sense, you could never consider any heavyweight as P4P in the first place.
Regarding the whole P4P vs divisions etc, i've always used the following guideline "all other things being equal" - aside from weight/height combo. So in that respect, look at where Usyk beat AJ last night when size was massively in Joshua's favour, it's clear Usyk is well ahead of Joshua in a "all other things equal" sense - if AJ was 6 3' and 221, Usyk would have stopped him easily mid rounds. Now, apply that to Usyk vs Fury? as it stands with Fury's massive weight and height advantages, many are now predicted Usyk to win - or maybe draw. How can Usyk not be P4P #1 in that case? Or put more simply, if Fury was shrunk down to 6 3' and 221, who would you pick to win? As others have noted it's as deeply flawed as anything else in modern boxing, but it's not rocket science to follow!