He's ok - but I'd consider him a disappointment given his draft position and expectations. Maybe I'm a harsher grader than you, which is why I label Maroney, Watson, and Graham "busts" - they contributed (a little), but nowhere near expectations and your team had no interest in retaining them past their rookie contracts.
A "bust" is as low a grade as you can really give a drafted player. Vernon Gholston is the definition of "bust". As is Jamarcus Russell. Neither of those guys, especially given their place in the draft, amounted to *anything* worthwhile.
I've already given you the actual numbers on those guys (the Pats' players). Ben Watson was the 32nd pick of the draft and gave the Pats, during his 5 full seasons with them, 417 receiving yards and 5 td a year. Here are, since 2002, the #32 picks in the draft:
2002 - QB Patrick Ramsey, Was
2003 - DE Tyler Brayton, Oak
2004 - TE Ben Watson, NE
2005 - OL Logan Mankins, NE
2006 - DE Mathias Kiwanuka, NYG
2007 - WR Anthony Gonzalez, Ind
2008 - DE Philip Merling, Mia
2009 - DT Evander Hood, Pit
2010 - CB Patrick Robinson, NO
Of this group, only Mankins has been an all-pro (or even been to the pro bowl). Watson and Kiwanuka would be the 2nd and 3rd best #32 draft picks since 2002, in some order (I could see the argument for Kiwanuka, though I can also see the argument for Watson).
Laurence Maroney averaged 779 yds and 7 td a year for the Patriots. He was the #21 pick in the draft. Here are other #21 picks:
2002 - TE Daniel Graham, NE
2003 - C Jeff Faine, Cle
2004 - DT Vince Wilfork, NE
2005 - WR Matt Jones, Jax
2006 - RB Laurence Maroney, NE
2007 - DB Reggie Nelson, Jax
2008 - OT Sam Baker, Atl
2009 - C Alex Mack, Cle
2010 - Jermaine Gresham, Cin
Maroney stacks up quite nicely with this group. Wilfork, obviously, is the best of the group, but Maroney's production is better than anyone else's on this list.
And Graham, again, was the best blocking TE in football for a while, and was a starter on two Patriots' SB-winning teams. You're not a "bust" if you're a key contributor on two championship teams. You're just not.
So, yeah, when you said, "Maybe I'm a harsher grader than you", obviously you are......at least when it comes to Patriots' players. Because you seem to think quite highly of Jets' players that have similar production to Pats' players (i.e., Keller).
Bottom line: clearly I can't change your mind, which is okay because you're also out of it.