Ruiz is a candidate for sure. BUT, Ruiz got dropped in the process. Beterbiev went wolverine on his ass
he will fight for 5 more years and than retire, people will remember the steamroller who hangs out with Chechen warlords and autocrats.
It's the perfectly straight hairline and the lack of forehead caucusus people have which makes them all look alike.
Proportions aside, he's a little like Froch. He has a lot more boxing skill than people think and throws a lot of those short power punches, almost from the hip. Since he fought at basically cruiserweight before in the amateurs, and has good power, if I was him I'd roll the dice at HW before retiring. Who knows, he could weave inside and take out a Wilder or Joshua on a given night and win a belt (assuming they have one). Not saying he's a favourite but he probably has enough skill to pull something like that off. I think he could beat Ruiz or shorter heavies. I'd be surprised if Ruiz/Parker etc. had more power than him, really, they're pretty fat at the weight. I think Beterbiev has enough power potentially to hurt HWs. It's not tested too often, LHW going up to be dangerous at HW, so sometimes it's hard to imagine, but this happens in MMA, where similar sized guys go up and have the power to KO big heavies.
I'd pick him over Ruiz.....no joke. I think he would wipe out Ruiz, regardless of how high Ruiz' confidence might be right now.