I am going to be incredibly generous and say Schottenheimer body of work is at best mediocre.
Does this tweet stop at 2015, though?
The next time he was an offensive coordinator, he had the league's top rushing offense and Wilson had his best passer rating, as was pointed out by the OP. Even when he got fired in 2021, it was the year that Seattle set a franchise record for points scored. However, much like with our offensive coordinators, he was out after a playoff failure.
I agree that most of his work is mediocre at best, but there are a couple of high points in there. I think the OP's point was he's been reunited him with the line coach with whom he had some of those high points.
I'm not feeling too confident overall with the choice based on his track record, but if we brought both of them in to improve our running game while McCarthy focuses on the passing game, I don't feel it's as shaky as it might seem. We'll see how it goes, though.