I understand the perspective. The OL is the straw that stirs the drink. But I do think it's important to remember they return 4 of 5 starters and 3 of 5 in the same positions. Not many teams have better continuity than that. With Whitworth, can he hold up for 17 games? That's the question. They will pace him accordingly all year I'm sure. Ability-wise I think he's still (incredibly) a top 6-7 LT in the league.
I think Havenstein proved 2019 was an anomaly and that overall he's a very solid RT (who will have some issues with elite speed rushers). I think they decided quite a while ago (February) that Corbett was going to be the center and haven't looked back. Having been in the offense for 1.5+ years now he can handle the line calls (a huge aspect of what made Blythe effective) and he's developed into an effective run blocker.
And I also actually like their depth. Noteboom as a backup LT, Anchrum, Brewer on the right side. If Shelton can prove to be a decent backup center that's as much as you can hope for from OL #s 6-9.