Both went in just the opposite direction, Haye concentrated on his Fitness & Power and Solis although still has very fast hands and his timing is still one of the best, increased his weight significantly. That said his only blemish was a very unfortunate loss due to injury (although this is also true that it was a result of a legitime knockdown), but without that injury he could have been able to continue a very interesting bout until that point ... Therefore a fight with Haye would be completely different fight from the fight on that world Championship years ago. A big question is if Solis is still able to match Hayes hand speed as he could in that final in Belfast ...
I'd be confident in picking Haye the avenge his amateur defeat to Solis. Haye's gotten better while Solis has just gotten fatter. I believe Haye had only quite recently moved up to heavyweight when facing Solis yet still hurt him badly before being stopped. I can't see how Solis would now deal with the gap in speed and mobility.
Well I would not bet on that, ... if Haye connect flush and early he would win that one, but as the fight evolve he will have to eat a lot of hands from Solis and I don't know if Hayes will react in the same way he reacted in the amateurs when he just gave up trying!