As usual, I will take a different angle.
I agree with the health issues. But that is always the same. So assuming average injuries, these are the 3 keys for me:
1) BALANCE ON OFFENSE. I dont care if we run for 2000 yards or throw for 5000, but we need to be EFFECTIVE in both phases when we use them. One dimensional teams always come up short in too many games (that may be every game for a weak team or the critical 3 to 4 losses that hurt you as a contender.)
If you consider the Pats SB Champs vs the non-Champs over the last 5 years, there is an extremely interesting dynamic. We had a more "high-powered" offense in 02 and 05 than we did in 01,03,04. Brady threw for the most yards of his career in 05 and the 2nd most in 02. Those were 2 of his 3 highest TD pass years, and the 2 most attempt seasons. If you look at the difference in the Pats in those seasons, forgetting defense for a moment, in the non SB years we lost games by being one dimensional. Whether that resulted in falling behind, turnovers, or being unable to come back late in the game after never establishing the run, we lost games where we have streaks of ineffective offense. In the SB years we won these games by extending drives with balance, keeping the D off the field, and hanging in there to be in a position to win the game in the clutch, having set up a balanced attack to make the 4th quarter offense less predictiable.
Now, BB has always preached balance. He has always strived for balance. But in 02 and 05 ineffective running games made balance unattainable---at least in too many games.
How do we achieve this balance. (Note: the key does not seem to be being great on offense, but balance and effective, therefore able to put points on the board when needed or chew the clock when needed) We have the best OL we have had in the BB era. Most importantly our OL is a balanced OL., It is equally effective run and pass blocking--assuming it is all healthy. (A lot of last years problems stemmed from losing this balance due to injuries and having an OL after those injuries that was better pass than run blocking. We have hopefully a healthy Dillon, but have hedged that bet with Maroney. The track record of rookie RBs who start in the NFL is excellent, so the fear of having to play Maroney a lot doesnt concern me. Pretty much every good NFL back stepped right in and played very well at his first opportunity.
If we are throwing the ball very well and winning 31-20 games, there is more reason to worry than if we are boring on offense and winning 20-13 or 17-10. Over a 16 game schedule the abilities that win the 20-13 game or even the 10-3 game stay consistent, but trying to win the 30-21 game creates too many Sundays where something goes wrong.
Maybe a better way to put it is this:
-If we try to run away and hide with a big lead, if something goes wrong, we are not ahead and have made it difficult to come back.
-If we try to be patient, stay conservative and make the game come down to who makes plays in the 4th quarter, BB has shown he brings in and coaches players who are more able to that than any team I've ever seen.
I would much prefer to have to go 8-2 in close 4th quarters games (because of the makeup of our team) to have a 12-4 to 14-2 record,than to expect that a one-dimensional offense will have fewer than 4 days out of 16 where it is taken out of sync.
If things go wrong with balance, you are always in the game, and are set up to come bakc by being balanced. If things go wrong one-dimensionally, its one of those long days where we keep staying within 2 scores and think 'these are the Pats and Brady they can pull it out' after having failed with the exact style of play that you need to now succeed with to come back.
2) 3rd DOWN DEFENSE. We can find a lot of areas on defense that can be key. But the reality is that a BB team (aside from the 2002 team that lacked talent on the front 7) is never going to ruin a season because it cant defend the run. The talent on the front 7 today says this just wont be a concern. Our 2 gap system says we will allow some rushing yards. If we have the players to make the best run D ever we still wont rank in the top 3 in run yards allowed, because our system says 3 gain runs are fine, but do not allow 30 yard runs. We dont play run D to dominate, we play it to create a stalemate. 2005 was an aberration in getting beaten on big plays in the passing game. I have the ultimate confidence that BBs coaching and personnel ability says that when you get burned by something your philosophy dictates you can not get burned by (BBs defensive philosophy is 1st and foremost dont give up the big play) it wont happen twice in a row. I do not have to search for what the changes are, becuase its BB, and I am comfortable in knowing he has spent 6 months knwoing that is a key problem, cant happen again, and he is knowledgable enough that it is fixed. Blind faith? Not really, it is based on the coaching history of one of the best who has ever lived.
Looking over the D, the natural question is the talent of players covering WRs. I can see it both optimitically and pessimistically at this point. Samuel I like, and he is a capable starting corner. Is he more? This year will tell. Hobbs became a fan favorite and looked pretty good, but rookies playing half a season are VERY unpredictable to which way they go in year 2. Is Warfield a castoff who is through, or a good player who was in a bad system withbbad players around him? Gay fits the Hobbs question with one missed season due to injury added to it. Euegene Wilson took some hits among fans last year, but I think a lot of his perceived negatives were cases of him not blowing an assignemnt but being the next guy coming in to help the guy who blew it. In other words, if the corner is one on one and gets burned, Wilson sees this and tries to get there to help (when that wasnt his repsonsibility) we see Eugene Wilson as the closest guy chasing a WR going into the end zone. As far as pure cover ability I dont think you can find a better S than Wilson, and I think he will shine this year. Of course Rodney back will help, but if the other parts are Ok, playing a Sanders or Hawkins there wont hurt us too bad.
The key to the defense will be covering WRs, getting off the field and doing it on 3rd down. Again, historically, we had issues on 3rd down in 02 and 05, and did not in 01,03,04.
Big Plays. My third key is big play ability. Again as we look back over the SB and nonSB years, there were more big plays in all phases in the SB years. Long passes, catches and runs, 20+ yard running plays, defensive TDs and turnovers, special teams plays. It is very interesting to look back and see the vast difference in big plays in all of these areas in 01,03,04 vs 02 and 05. You could even say we made A LOT in the SB years and almost none in the nonSB years. Where will they come from? Some possibilities:
-Branch, Caldwell, and Jackson being able to run after the catch. All 3 have the ability to make a defender miss and get gone. I don't know if we have the 'deep threat' potential we have had in the past, but it doesnt really matter to me, because our deep hits have always come from gameplanning and setting up the play, not from just outrunning corners.
-Return game. To me the return game isnt about the returner but the blocking. I think an unnoticed effect of the numerous injuries we have endured is the return game. Backups become starters, and get pulled from some st units. Now the end of the roster who didnt 'make the first team sts' are the guys out there. If you look over our roster we do end up having some st demons, but also some players who are specialized at their position and not good special teamers. The additions of guys like Tebucky, Mitchell, Mills, Thomas, and potentially Mincey, Claridge, etc should make the blocking on sts better. Remember its not OL blocking DL on returns, its mostly WR,DB,RB,TE,LB players doing the covering and blocking.
-Defense. Our DL is excellent, young and improving. More disruption can mean more big plays. I actually think that Willie leaving will be good for Colvin. I think in the end we are going to see Colvin turn into a rush all the time OLB. BBs 34 Ds more often have one of the OLBs as the primary rusher, and the other as a sometimes rusher. Over the last 3 years, we have run the D where each OLB rushes as much as the other. There is benefit in that because it is not as easy for the offense to know where it is coming from, but a negative in that a guy like colvin is limited in rushing. The big key here in generating big plays is going to be the secondary and getting Ints. Historically BB runs a high Int rate D, last year we couldn't make picks. IIRC, that was an issue in 02 as well-but Im not positive. A key to the big play facet of this analysis on D is going to be a needed improvement in getting Ints.
If we have balance, play strong 3rd down D, and sprinkle in the big plays we have had the aptitude for in the past, this team will be unstoppalbe. (Of course there is the injury factor, but unless those injuries impact these 3 areas, we will be fine) I would even go so far as to say that we could sustain an injury to tom Brady---not season-ending though---and still be a first round bye team if we can run well enough that the backup can be somewhat effective and we keep balance, play well on D on 3rd down, and are adequate in generating big plays.
Not to downplay any of the other areas mentioned in the good posts in this thread as critical, but I think these 3 areas automatically equal success. When we have done it at least pretty consistently, we win SBs, when we are weak in these areas we are a good, not great team.