Not that they do not need an upgrade at NT. They absolutely do. And I may be wrong here but to me what Wade Phillips wants from his defense is sacks/pressure and turnovers. That is reason 1 they went out and got Peters. If they get gashed in the run here and there along the way so be it. Just my impression from him over the years. His defenses are not typically run defense dominant. TheyvRe about sacks and turnovers.
I think a bigger, better NT combined with Smart in year 2 can help them up the middle. Maybe they move Barron, maybe not. But he did pick off 3 passes last year and is better in coverage than Ogletree.
Another run defense factor is Quinn was not good vs the run last year in the 3-4. Longacre is better there. So maybe that also helps.
And frankly if they want better run defense then it should come from Ogletree. Get him making more plays (another reason to get bigger and better at NT).
Pass rush always covers up warts elsewhere. I think that is where they want to keep investing defensively. While also having the well rounded OLBs that they did not feel Quinn was.