I think that hendo has a better chance of beating silva overall, but vitor has a much better chance if the fight stayed standing. Hendo is a one trick pony in the stand up department (well, two trick pony if you consider him falling every time he throws a kick a trick). I know that his only punch is a damn good one, but there is no chance in hell of him catching silva with that big loaded up right.
He hit Silva with an over-hand right in their first fight. It even seemed to effect Silva a little bit. But by that point Silva was already moving in for the clinch, which I think he got a weird knee/kick hybrid off in. If what you're saying is he'll never hit Silva with his right hand the way he did Bisping, then you're absolutely right.