Here's what I worry about, in order of worry
(1) Ninkovich is one year slower and wasn't that fast last year either, Long is gone, Sheard is gone, Ealy is unblooded and Flowers cant do it alone
(I'll say this. Last year I loved the fact that our DE's were so versatile but esp in the run game. It was unique group and one that I really loved but the addition of Ealy, Rivers and Wise Jr is also extremely unique in its own right. Even tho hes a rook Rivers will bring an instant impact off the edge. Even if it's just on 3rd downs/obvious passing downs. Wise Jr is another long guy who was absolutely loved by his teammates and coaches. He'll fit right in and is someone I expect we move around some. It's a younger group but I'm very happy. We have multiple pass rushers that will come at you from everywhere)
(2) we forget how good Marty Bennett was
(This is true but imho his biggest asset to us was his blocking. He was a beast. Allen will take on that role with no problem. He knows his role and will play it. Our offense has 600+ point potential)
(3) we may find that Logan Ryan was much better than we thought at the time
(Similar to the DLine we might lose a little in some area, although I really don't think it's much. And gain in others. I'm a huge Ryan fan. Would love to have kept him but Gilmore and Butler might be the best in the league. When you add in our S's its just another embarrassment of riches)
(4) a bad hamstring at OT (knock wood) could be real trouble for Brady
(This group is versatile and knows each other very well. Over the past few years they've been through so much. Terrible group that killed the season to a legit strength (which I thought they'd be b4 the year). Year ender, that will hurt any team but we could survive 1-4 games)
(5) turnovers happen
(Not sure what exactly you mean here?)
(6) Belichick may trade just about anyone at the most inopportune moment, like he did with Milloy, Collins, Mankins...and some roster spot that we think is all sewn up may suddenly have a gaping sink hole
(Bill knows his team better than anyoneand its not close. This is something he gets the benefit of the doubt 100/100)
(7) Patrick Chung...I'm just not sure
(Chung is a football player who like Ryan improved each season. Tough gamer who will always have his flaws but does his job more often than not nowadays. Our secondary is a big +++ and he's a big reason why)
(8) will the culture take with the newcomers, Gilmore, Cooks, Allen, Gilleslee? I don't worry about Burkhead for some reason. Bennett and Long were instrumental in adopting and setting the culture among the incoming veterans