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
(2) we forget how good Marty Bennett was
(3) we may find that Logan Ryan was much better than we thought at the time
(4) a bad hamstring at OT (knock wood) could be real trouble for Brady
(5) turnovers happen
(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
(7) Patrick Chung...I'm just not sure
(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