Sure he's clean now but his body was built using EPO.
EPO is not a steroid, and it doesn't build bodies, however, I'm taking your statement in the narrow sense there, so let's rephrase.EPO gives you more RBCs, and it does have out-of-comp advantages, but it also has disadvantages. You don't boost your anerobic threshold, for example, by training with an artifically raised threshold, and then going to comp without it. Cav's an out-and-out sprinter with legs made of tree-trunks. Everything he does that is remarkable is in the anerobic regime. I would be profoundly sceptical of a claim that he's in materially better condition that he could have been, had he never doped.
People cheat. It's a very bad thing. If you think the correct response is a lifetime ban, then fair enough, but that has to be across the board. I don't think it's fair to ask whether a given former cheat may have a material advantage later on, and another not. So, let's not argue Cav's abilities in relation to former use of EPO, but let's ask what the penalty for doping ought to be. If you genuinely believe a lifetime ban to be the automatic response, then so be it. Otherwise, you really must conclude that he's served his time.