Getting back to the topic of bigger RBs
Last time the Patriots had a bigger RB that was a big part of the offensive game plan was when they had Antowain Smith and Corey Dillon. What made them successful was they were able to gain short yardage just often enough to move the chains, and, during the end of a close game, they both stepped up their game to run the ball consistently enough to move the chains AND run down the clock. I think most would agree that while Smith and Dillon were with the Patriots; neither could break one over 10 yards very often. So, apart from Dillon's 2004 effort, they had not really been a top 10 team rushing leader with a bigger RB. Besides, it was more how they used their RBs. The Patriots did not blow away teams regularly. They kept themselves in games, and won quite a few close scoring games.
By 2005, Dillon's production went down. In 2006, Laura Baloney joined the team and BB chose to go with Running back by committee.
I think there's a lot to be optimistic about re: RB position. They might want to add a RB for depth, but Bolden, Ridley, and Vereen is a pretty darn good corp. I think they have a couple of choices here. Add a FB for depth, or keep who you have and use Bolden for short yardage situations. If Gronk and Ballard aren't on the team/field at the same time - it would be a good idea to pick up another blocking TE or a FB. Another TE can vie for a spot vs. Hooman and whoever else is still on the roster.
2002 = #28, Faulk, Edwards, Redman
2003 = #27, Faulk, McCrary, Redman, Pass
2004 = #7 Dillon, Cloud, Pass (TE Graham)
2005 = #24 Dillon, Cobbs, Eckel, Faulk, Pass (TE Fauria, Graham, Watson)
2006 = #12 Dillon, Cobbs, Faulk, Thomas, Baloney (TE Graham, Thomas, Watson)
2007 = #13 Evans, Faulk, Baloney, Morris (TE Brady, Mills, Watson)
2008 = #6 Eckel, Evans (FB), Faulk, Baloney, Morris (TE Watson, Pollard, Thomas, Spach)
2009 = #12 Faulk, Baloney, Law Firm, Morris, Fragile Fred (TE Watson, Thomas, Baker, Smith)
2010 = #9 Faulk, Boloney, Law Firm, Morris, Fragile Fred (TE Crumpler, Gronk, Hernandez)
2011 = #20 Faulk, Law Firm, Ridley, Vereen, Woody, Polite (Gronk, Hernandez)
2012 = #7 Bolden, Ridley, Vereen, Woody (Fells, Gronk, Hernandez, Hooman)