I think the most reliable way to survive these days is to be a good offense with an opportunistic defense. If I were to build a team, that's how I'd do it. In order to have the defense we have, we've had to invest a LOT of draft capital in the front seven, and it hasn't paid off. Our pass rush is anemic and we haven't gotten a lot of picks in recent years, other than this one.
Sure we have a top five young MLB and a top five nose, but what did that really do for us? Not saying they're bad players. Williams is arguably an outdated model, and Mosley is a MLB, which, these days, is not a really impactful position, unless they can man cover the top tight ends, which Mosley can't. They are run stuffing positions. I'd be inclined to build around a pair of pass rushers (inside or outside) and two strong DBs. Those are the defensive building blocks you need today. A pair of pass rushers and a pair on the back end. We don't really have those building blocks.
DL and DB need to be our talent-focus on defense.
On offense, I like the idea of investing everything in the line, and getting a couple sure-handed receivers that fight for yards, a bruising running back, and a Gronk-type tight end who can block, catch, and break tackles. (I'm saying Gronk type, not Gronk level). If it sounds like I'm describing the Patriots, it's because I am.
OL, QB (of course), and either WR or TE need to be the focus areas on offense, if you ask me. If your line is good enough, a no name like Justin Forsett will be good enough. If that no name can catch, then that's even better. Having a top five tight end adds a lot to an offense. Blocking, mismatches galore, and the chance for a lot of YAC after broken tackles, along with the occasional jump ball.