The question asked needs to be more precise IMO.
In their prime, probably some guy from Japan at some point. That's all I can say.
Best in ring workers I have seen are D-Bry, Eddie Guerrero and Chris Benoit. Whereas the best all round performer I've seen is HBK. Even Undertaker when it comes to portraying his gimmick in the ring, and performing in big match situations. He really captures the storyline as well especially in recent times. I mean his last WM match that was under 4 stars was probably 20 (Aside from 27 which I'd have at about 3 and a half) so he could be known as one of the best wrestlers ever?