[Monfils] is faster and more athletic than Nadal, Djokovic, Murray... and generates just as much power with his serve and groundstrokes as the biggest hitters on tour. He has the potential to be a big hitter with tireless grinding abilities.
See, I actually don't disagree with any of this. I just disagree with is the notion that he's an underachiever because of those things, as he's never shown that he knows what to do with it all. His tennis IQ is virtually non-existent, and I'm not sure anything short of a brain transplant will mend that.
The difference between him and actual underachievers, in my mind, is that, to my memory, he's never produced the brilliance that his qualities would suggest he's capable of. Nalbandian, Safin - we've seen those guys produce the level of tennis that suggest they should (have) achieve(d) more. With Monfils, as of now, everything to this point has been suppositional.