I see DL and OLB as huge needs for the 2012 draft.
Anytime BB has to bring in veteran retreads like Haynesworth, Carter, Ellis and Anderson, that just tells you that something is hosed up big time.
Moss (30) = Stud coming off bad team situation, attitude questions
Elite production for a couple of years before self-destructing.
Haynesworth (30)
Rodney (31) = Vet supposedly on downside, cap casualty, motivated for ring
An amazing 2 year run, including two titles, before starting the real decline
Carter (32)
T.Washington (35) = Tough, smart aging vet, brings experience and stability
Placeholder until an elite replacement could be acquired
Ellis (34)
B.Hamilton (29) = Potential but declining production, looking for 2nd chance
Shot in the dark that helped pave the way for the title years
Anderson (28)
Not all situations work out and I could cite negative examples as well. Each of the cases above were critical in winning titles but each could have (and did) receive the same criticism you are levying now.
The fact that all these acquisition are on the DL is just a case of value meeting opportunity. Belichick knew that a boatload of DL candidates would be available. Given the multiple fronts he wants to use, the lack of an offseason and the presence of several tough pass-first teams on the schedule (Colts, Steelers, Bolts, Eagles) this was not the year to go young on the DL.