The biggest impact should depend on the opponent also. If Lenox returns to fight Wladimir or may be if Vitali returns for a rematch, will have a great impact. But, may not be the same if he comes back to fight some other HW. In the case of Tszyu a rematch with Hatton does not cause me a lot of excitement because I think Hatton will dominate even easier an older Tszyu. However, a come back to fight Judah may be more interesting.

In the case of Tito, the biggest impact may be fighting De La Hoya, but the difficulty I see is to have King and De La Hoya agree $$$. Tito may have some other options such as Mosley or Taylor, even rematches with Hopkins or Wright. But, the fight I think he should not take, but probably will sell well, is RJJ. I have to admit that RJJ will be too heavy for Tito, and have all the advantage in this fight (and this is hard for me to admit). The best chances I see for Tito is, if RJJ accept to go to 168.