I think Buckley is about to retire Usman decisively. I don't even think it's going to be competitive and Belal's going to need a bit of time off, lol. Welterweight historically is not the division that guys move up into and have sustained high-level success. BJ had some success at it, but he really wasn't a great WW. Not many guys went from LW to WW and killed it.
So Islam at WW to me is pretty meh, and it isn't a huge needle mover for me. Honestly, if Islam was content to run another 3 or 4 title defenses at LW, he'd easily be the LW GOAT without question. I think he can win some fights at WW... but switching between LW and WW is a recipe for disaster, and Islam better get used to fighting guys that are bigger and stronger than him quickly. Kudos to him though if he really is down for testing his mettle at WW full-time.
And like it or not, Belal is still a top welterweight when he heals up. I think he will also be in for a rude awakening if he thinks he can duplicate Whitaker's success transitioning from WW to MW.
That being said... currently, I'd like...
JDM vs. Shavkat
Brady vs Buckley (in the next eliminator)
Garry vs. Colby
Prates needs a stand up guy and I doubt WB would take that fight but he's the perfect stepping-stone fall-guy. The only reason WB takes that fight is to show off his testicular fortitude, because he will get beat up badly.
I'd also like to see MVP vs Adesanya at 185lbs while the WW and MW divisions sort themselves out, and Ilia vs Paddy seems like it would be a damn fun fight if Islam ends up fighting someone else.