"Right now I have to say Adam Scott is tops on my list.
When I say underachieve, I mean in total wins...not so much rating them on Majors (although they are factors as well) because I know how many people like to bash Sergio, but he has a lot of wins on various tours...I'm looking for someone that is really a disappointment..."
I understand what you are saying, but I can't say winning 15 times between the PGA, Euro and Asian tour (since 2001 when he was a full pro) qualifies as a failure any more so than Sergio whose only won 19 times between the 3 tours (since 1999 when he turn pro). In my opinion, if you don't rate them on majors, I can't rate them so much on one years performance plus Sergio has had two more years on tour than Adam so you would expect him to win a couple more times, nothing earth shattering though...
My biggest disappointment on the tour is Charles Howell III.