Not worrying about the D until after the midpoint of the season, especially since the safeties are the lynchpin in this scheme and until Bishop gets up to speed with games under his belt we won't see the true effects...after the midpoint, I would expect the D to continue improving and hopefully finally peak during the playoffs for once.
Also a lot of new faces and rookies in there that need to get acclimated to the scheme and learn how they best fit in their roles within it.
But what's Baltimore's excuse with 7 first round picks and multiple All-Pro and pro bowlers on D that has largely remained the same from last year including an "All-World" secondary that got absolutely shredded by Allen giving up almost 400 yards passing and 500 total.