Sorry to say, but I think he's past it already. He's had one world class season, followed by a decent season(seeing as he was injured half the time), followed by his possible decline in the third. If he fails to recover, will he go down as a good or bad signing?
I think it boils down to this: do you think we would have won the 2013 season without RVP?
If the answer is "no", then he was a good signing after all. But if the answer is "yes", then I struggle to see how this was a good signing. He alienated Kagawa, Welbeck and Hernandez and forced us to try a weak partnership(Rooney + RVP). I think the team as a whole would have been much better off if we never signed RVP. But it remains to be seen. If he recovers, then I might have to eat those words.