It never ceases to amaze me how quickly people are willing to tout a fighter as the one to dethrone GSP. Haven't we been down this road before, numerous times over the last half dozen years? Tenacious grinders. Heavy handed strikers with elite wrestler. Elite strikers with elite BJJ ground game. Elite strikers with top level take down defense. Elite grapplers. Elite strikers. Elite wrestlers. Everyone one was supposed to have the skills do expose GSP... and he 50-45 all of them. The reality is GSP has faced everyone combination of combat skills short of matching up with someone as well rounded as himself and he has outclassed all of them. By a huge margin. Since GSP won't fight Rory, Hendrick is last litmus test for GSP, and Hendrick only a harder hitting facsimile of Koscheck with a much worse gas tank.
No fighter at WW has the skill set to beat GSP. That's not to say he is unbeatable, obviously there are fighters that given the right circumstances could pull out the win with the right about of luck, but if GSP fought all his challengers ten times, he would win an overwhelming majority of those fights. Now time and injury will eventually catch up with GSP and he'll have either retired or he'll start to lose, but prime GSP at the best of his abilities is the best. Period. There isn't a fighter active today at Welter Weight that can beat him by being the superior fighter.