hiring a college OC may have been a mistake...

[Ozzy]

I've said it before but it is highly likely that Geno likes and wants to be in shotgun. O coordinators run what their QB's like and are comfortable with.
Simply blaming Grub for their shotgun heavy approach is silly.
If Geno wanted to be under center I'm quite confident he would be under center much more.
Geno likes looking over the defense from back there and dissecting what he wants to do.

I fully believe this and with pass protection not being good(although maybe getting better) it was a necessity.

Grubb is widely known as an offensive genius. I seriously doubt he doesn’t know the benefits of under center vs shotgun. It’s obvious he’s doing it for a reason like you listed. I think sometimes, especially when it seems like such an “obvious” fix, they probably know better than we do why they’re doing it. I’m going to give Grubb the benefit of the doubt.