One back-of-the-envelope way of thinking of things is how expensive or cheap various position groups are. I have NOT looked up actual numbers, but I conjecture it runs something like:
QB -- Fairly expensive, although a bargain even so.
RB -- Cheap, since the lead guys are rookies.
TE -- Expensive, whether or not you include any Hernandez money.
WR -- Cheap, Amendola notwithstanding.
OT -- Moderate, becoming expensive when Solder gets his deal.
G/C -- Somewhat expensive because of Mankins
CB -- Fairly cheap, but Talib aspires to change that after this year.
S -- Fairly cheap, but apt to get expensive once McCourty re-ups.
LB -- Moderate now, since Mayo is the only expensive-vet contract.
DE -- Dirt-cheap.
DT -- Moderately expensive, solely because of Wilfork.
Special teams -- Moderate, since Gostowski & Slater are the only ones getting paid much.
Seems like an OK balance, for now -- especially if we can get a strong pass rush without paying for it.