Just look at their body of work outside of the Seahawks, it's not good.
It isn't possible to evaluate the effectiveness of any of the OCs in Seattle to date because of how seldom the plays were actually adhered to. That's not spitballing. It's been fairly evident and consistent since Russ has been here. It was blatant last year, and highlighted in 2020 because of how quickly the offense fell off from high heat to simmer, when defenses, as they had in the past, figured out the latest trick our QB deployed.
There's a video out there on a Denver site pretty clearly documenting the offense that Russel runs, irrespective of who the coordinator is. He has a basic read and then check or alert that he goes to that he's pretty deadly with, but that becomes beatable with a defense that has better safety play and that can take away the run.
Whether he's checking out of them because he doesn't like them for whatever reason or they won't work. . . Hard to tell. But the majority of his money was made on alerts, checks, PA and plays hed just extend to reset the field. The plays that weren't checked out of... those are the instances in many cases where on tape, you have players open, and Russ would pull the ball down to extend the play or in the old days, just run. Or, he would opt for a route he felt more comfortable throwing to.
True, Carroll's correction has been to push a more run based approach. But if you can't pass your way around a problem and your qb has for a decade, played the same way and shown the same tendencies... what other options are there. And as was evidenced last year, sticking to the running game and passing off of it, rather than having a pass heavy run / pass split (which last year we lost all but one game when we passed more than we ran), is a viable complement to Russ style of play.