Henderson should have won last time, but he made some pretty costly mistakes. Anderson Silva has been lacking, maybe in motivation recently, his bouts at present are so...inactive...that he might as well be on a mantle collecting dust. This of course wont apply when he fights outside of his weight class. Lets see how he does v Griffin...because that will show, hopefully, his present level when pitted against a moderate threat.
If he struggles, then Henderson will zap him, if he fairs alright then it should be more competative. I still think, bar a serious mistake like last time, Henderson will be able to win.