Gilmore was great for the Pats. Sad to see him go. I also hope that the secondary can be strong without him. So far they've been solid. The defense is #6 in the NFL in points allowed, #5 in the NFL in yards allowed. And that's without creating a lot of turnovers or having their offense give them tons of help (#27 in points, #26 in yards).
NE's pass defense ranks:
#4 in pass yds/game (185.0)
#3 in pass completion % (56.5%)
#6 in net pass yds/att (6.5)
#2 in passer rating (67.6)
#10 in sacks (10)
To be fair, they've played three of the five worst passing offenses in the NFL (NO, NYJ, Mia), so that obviously helps. But they also did a pretty nice job against Tampa, all things considered. In better weather, maybe Brady shreds them. Probably. But who knows. The pass D made some plays. So maybe their pass defense is actually pretty solid even without Gilmore.