At the beginning of the year they started Sanders at FS while BM acclimated. Then Rodney got hurt. Rodney has started every game at SS when he was healthy. BM developed and shows a big up side, and now BM is FS. Sanders is SS and has yet to show he can do the job IMO. People who cliamn that a defense that was horrible against the pass (esp stopping big plays) and lost two of its greatest players in Vrabel and (likely) Harrison is somehow better now than it was last year because they have two new corners have some sort of special knowledge I suppose. The defense is not "complete". It is improved at CB and nowhere else.
No it is significantly stronger now. In 2008 they had rookies Mayo, Guyton, Crabel, Wheatley Willhite and untested Meriwether, Richardson Lekevin and Woods. They had an all Pro HOFer, trying to return from injury in Richard Seymour. They had newcomers Jason Webster, Deltha O'Neal and Lewis Sanders totally unfamiliar with their teammates or the playbook.
Today they have Richard Seymour all the way back with his 8.5 team leading sacks and team leading 16 pressures, in 2008. Mayo, Meriwether, Le Kevin and Woods were tested and proven to be at least adequate players. Guyton, Willhite Wheately and Richardson with a little experience.
Bodden has played this system even if not with the Pats. TBC knows the system and can play as a spot starter, too. Springs is a newcomer who has to prove his stuff, but he appears more talented than last year's vet DBs. Bill should know, and he is paying him a lot more.
More importantly the Offense has a now feared and very deep running game, to go with the awesome passing game. Along with a league MVP QB, too. They have a genuine, real blocking TE too, to help that clock killing and Defense resting while off the field, now passing and running Offense.
It so true that Vrabel is is gone, but Bill must have decided that Vrabel was losing it. Welcome Woods Redd, Crabel, TBC, and the expected drafted newcomer to try and fill his shoes. AD has come back from his broken arm. Rodney's best days were in 2006 and 2007, He was a shell of his old self, in 2008.
So they are more talented and deeper at DL, OLB, ILB, S and CB and on Offense at QB, OL, TE, and RB than in 2008. They are less certain and possibly weaker at WR. What's not to like?