I don't know who would be the best but in recent times Joe Joyce has a good argument when you consider he holds wins over Parker and Dubois, with their current Ring ratings of numbers 3 and 2 respectively Though I expect some may point to the Zhang fights after I wrote this, as he has 2 wins over Joyce
I'm saying most who recognize belts other than the "main one" wouldn't recognize the early WBO belts. For me the date the WBO became a real belt depends on division. For me it becomes major in 2000 for HW and WW, 2004 for MW and 2013 for LHW. I don't pay attention to SMW but that makes sense.
I think Povetkin was largely thwarted by Klitschkos controlling all the belts, Wlad with most and Vitali always delaying fights with injuries. Even without the octopus cheating, Wlad probably still wins in a shootout but Povetkin has a better shot. Then Stiverne gets lucky because he fights for the belt when Vitali finally went away. Povetkin in that position would almost certainly win the belt, quite possibly beat Wilder and then have a decent run. However, Fury would also have likely beaten Povetkin unless he fooled around. Size difference is immense. So he would probably stop Povetkin dominating. But back to Povetkin's actual path. He had a few more title opportunities but the Wilder fight was cancelled for traces of an over-the-counter drug and then he had to fight AJ pretty old. Those were winnable fights in his prime and the Wilder one was winnable then as well. After that he beats Whyte in an elim then has to do it twice and this time has Covid fallout and can't perform. So he was pretty unlucky, yeah.
It is absolutely no one's fault but Povetkin's He made a career out of avoiding title fights and fights that would lead him to a title fight. He opted for lesser belts and high ranked competition that has already surpassed him for a title shot, failed, and are fighting him before they're totally out of the ratings. 2008 would be Pov's first chance to duck a title fight 2013 he gives his balls a tug. 2008-2013 men debuted, went up the ratings, and fought for a title without ever having to fight Pov because Pov never positioned himself to be there. Stiverne passed him up, sure, so did heaps of dudes who lost to Wlad and Vitali, so did most of Pov's own resume because he didn't even fight his name wins until after Wlad beat them. Then he askes for more time as the Silver champion at a press conference, and gets it. He fails a drug tests and loses another shot at a title. Poor, poor Pov, it's really the K2 bros fault he was so scared of them he wouldn't touch anything that might lead to them for the majority of his career. Poor poor Pov, tried to age out Wlad and just aged himself out. So super talented against fat jamook no hopers that have already lost their bid for a title that Martin became a champion without ever seeing Pov. Dude wasn't a gatekeeper because he ducked the role. He was nothing more than Wlad's garbage disposal for Wlad to send his leftovers to. At best.
I'd argue it's Luis Ortiz: - Won the 2005 Pan American Games in Brazil and the 2006 Cuban National Championships - KO'd 6th ranked Jennings in 7, who was coming off a 116-111 decision loss to lineal champion and P4P No.2 Wlad - Beat several other mutual opponents of contenders/champions in impressive fashion (Z. Page, Thompson, Allen, Cojanu) - Avoided as an opponent by Ryabinsky/Povetkin in 2014 and Hearn/Joshua in 2016-2017, got his first title shot against Wilder on the cusp of 39 (rumoured to be older), unbeaten in 30 fights with 28 inside the distance - Top 6 in Ring's end of year heavyweight rankings from 2015-2020 - Got off the canvas twice to KO former titlist Martin: the most significant win for a 42+ year old heavyweight since Foreman beat Moorer - The most accomplished Cuban professional heavyweight since the 50's, if not ever - "I can understand people believing (a post-Wilder 1) Ortiz would beat the likes of Whyte, Parker and Miller in a fight as he has the skills to do so." - @Mitch87