It is still unclear to me what Bivol's ceiling is. For now, I would have to go with Conn. If Bivol dominates Beterbiev, I might reconsider.
it's a good match on face value, a nice Era vs Eras' consideration, however there are a few things to think about... 1 - Conn is not the best L-HW ever, there are a good few, a damn good few, though it is a division that gets lost in time. 2 - Bivol, though impressive only boast a handful of top names, where as most of the historical L-HWs boast a whole lot more, including more Top & Noted fighters too. 3 - How good would he be facing some bigger men like many of the great L-HWs before him. 4 - Number of fights, it is ALWAYS a factor, i.e RJJ's, Tarver, coming along sooner the more Top men you face nearly every time out, again, is always a factor with busy multiple number of fights. Conn and Co already done it, successfully. 5 - We will have to see, which means waiting, which sadly, might mean waiting on Never, such is Modern Boxing. 6 - an RJJ mythical match up might be a better starting point, before the Conn's, Moore's, Charles', Marshall's and many more.
Lt Heavyweight champ from 1939 to 1941....beat 10 former or future world champions in his career....ALMOST beat a prime Joe Louis in June 1941...Take Billy Conn every time. A proven all time great!