After losing to Seattle/Wilson, NE has faced Fitzpatrick twice, Kaepernick, Goff, Flacco, Siemian, Moore and Osweiler. I don't think we can definitively say if NE's D is good.
I don't think you can simply ignore the fact that they're number 1 in scoring defense and number 8 in total defense. Maybe their schedule helped those numbers, but they simply can't be summarily dismissed
TEAM | WEI. DVOA | LAST WEEK | W-L | WEI OFF DVOA | OFF. RANK | WEI DEF DVOA | DEF. RANK | WEI S.T. DVOA | S.T. RANK | TOTAL DVOA | RANK | |