Just as he did with many other fights, Joe would never take this fight... and if he did, he would get viciously KO'd, which is why he wouldn't take it. Maybe if Beterbiev was completely washed up or even in his 40's we could potentially see this fight.
Calzaghe would never take the fight. If he was somehow forced into it, I would bet my life and the lives of everyone I care about on Beterbiev.
Slapping is not going to deter Beterbiev. Calzaghe will have to make stand somewhere and on that hill, he will die. The problem that Beterbiev presents is that his punches do damage from close quarters and at times, are not seen by the opponent.
There are not many folks I'd pick over Zags, but Beterbiev is one of them - he's a monster, and to win Joe would have to deliver a Lacy like A+ performance - he is capable of that, but Artur is a very different animal than Lacy. Joe has a granite chin, but AB seems to be so heavy-handed he can discombobulate opponents with short, even glancing blows to the top of the head. This would be an interesting fight but @175 (where Joe only fought twice) i'd have to make Beterbiev the favourite for sure - like 60/40. That said, next to Bivol, Zags probably has one of the best shots of pulling it off - insane engine, high IQ, angles and footwork. Whilst i'm sure both could make Artur look ordinary - even clumsy - at times, the chances of keeping him at bay for a whole 12 rounds? That's the real nightmare on facing Artrur - he seems to carry his power and gas tank all the way to the end, and WILL connect hurtful shots thought the fight. 2 additional downsides for Zags in this - I think ABs bones are really dense and his hitting napper is a bit like hitting concrete; that would spell disaster for Zags brittle hands. Additionally, JC always had a tendency to neglect his skills and get drawn into a tear-up - I think he would be way to savvy to do that against someone like Artur, but it's a consideration. Until we actually see someone execute a gameplan that exposes some weakness in AB that shows he can be outboxed, it's very difficult to suggest that anyone south of 200 would be favourite. What makes that a bit cloudier is that AB has not faced a truly elite slickster with the mental fortitude to be able to execute that plan - Gvodzyk was arguably elite - but he couldn't execute and possibly didn't have the 'cold iron' of a Bivol or Zags. As it stands, because no one has even really been that close to taking him the full 12, it's hard to see how someone does it - with the Gvodzyk beatdown a really large piece of evidence to consider. Could Zags or Bivol have beaten The Nail? (yes I know triangle theory but still) Tbh there's not many @175 i'd make favourite to beat AB H2H - Moore,Charles,Foster,Spinks & maybe prime RJJ. Even those are so in the mists of antiquity it's hard to say. Recently only prime Kovalev has a chance due to his excellent jab. But that weakness to the body means I'd still favour AB.
Beterbiev is a potential ATG at LHW Calzaghe was never a career LHW and he got dropped TWICE by two shot fighters in Rd1 when he stepped up to LHW. Now tell me he can weather a Beterbiev storm ......