Re-sign Welker, Koppen, Connolly and Carter
Sign Brandon Lloyd
Add a WR who can fill Branch's role, or be another middle-deep threat
Add 2 DE/OLBs
Add S
Add CB
I agree with your needs. Only add to the signings of free agents is Mark Anderson. Bring back Carter and Anderson and use the first pick on another defensive lineman. I'd use the second 1st rounder on another offensive lineman - a center or a tackle.
The Pats will get better, in 2012-13 I believe, especially as the defense matures. The oldest positions among the guys who play lots of snaps are defensive line and WR. The defensive line is already part way through a make over, so I expect one of the #1s to be defensive down lineman one to be an offensive down lineman depending on whether Connolly is a true center in the coach's eyes.
Oddly, I love the current defensive backfield - very young, quick, and now battle-tested with an 18-game season. The early season roster gyrations made a mess of things early, but these guys got much better as a unit down the stretch, especially when Chung returned.
Watching the core DB group - Chung, Arrington, McCourty, Moore and Ihedigbo - kept making me think about Ty Law and Rodney Harrison who both came into their own as DBs and leaders at around the age of 27 - 28, older than all of these guys, except Ihedigbo who is 28. Harrison was 31 his first season with the Pats. What we must remember about Ihedigbo is that he never started an NFL game until this year.
If there is a Harrison or Law caliber free agent out there to add to the mix, they should try to get him, but those guys are so expensive, it seems like you have to grow your own or risk messing up the cap balance the way the Eagles did. My feeling is that this is a good corps to keep and further develop with a full off-season ahead. I'd try to add one more in the draft, but that is a complete crap shoot as we've seen with other promising picks.
The Patriots offensive line and backfield are going through their own rejuvenation with the pieces in place. At receiver, Welker has three more years in him, the TEs are spectacular and wideout needs a makeover with Branch near the end and Ocho all but useless. That is the position that Belichick will probably stock with all sorts of free agents including Brandon Lloyd. WR is like DB. The really good ones cost too much and the draft is loaded with potential but mostly misses who cannot adjust to what is needed at this level.