The Patriots are only graded this low because the reporters want to (and should, to an extent) make a big deal about how the Patriots let Welker go to the Broncos, and have yet to adequately replace him in the offense or overhaul their defense.
In truth, the Patriots are already championship caliber (as evidenced by last 2 seasons) and only need complementary veterans to an already strong, youthful core.
The roster can be generalized as follows:
QB: Brady Mallett - Arguably greatest QB ever and a young, promising backup. (A+)
RB: Ridley, Vereen, Bolden, Washington - A dynamic 1-2 punch in Ridley-Vereen who are waaaaaaaaaaaaaaay more explosive than BJGE and Woodhead. Bolden and Washington are good ST contributors and solid backups. (B+)
WR: Amendola, Jones, Slater - Slater is Special Teams only, and both Jones and Amendola, while possessing tremendous upside, are very injury prone. This position needs to be filled out in a big way (C-)
TE: Gronkowski, Hernandez - Best TE combo in league by far. Durability is a question, but their injuries have been kind of freakish, so they can be given the benefit of the doubt (A+)
OL - Solder, Mankins, Wendell, Connolly, Cannon - A solid, young OL under Coach Scar. Just add depth and perfecto. (A)
DL - Jones, Ninkovich, Wilfork - A deep position, yet not many "game changers." This is where a draft pick or Abraham could help. (B)
LB - Mayo, Hightower, Spikes - Big, strong, imposing. But lacks in coverage ability and proven depth. (B)
CB - Talib, Dennard, Arrington - If Talib is healthy, Dennard is out of jail, and Arrington is in the slot, the team may be on to something. (B)
S: McCourty, Wilson, Wilson, Gregory - If A. Wilson can contribute and T. Wilson can develop, the Patriots now have a solid Safety group (B)
So outside of WR, CB, and DL to a lesser extent, the Patriots are very much ready to go.