I don't think the OC has to call plays to have an impact. He just has to have some input, especially in the run game design. He also needs to have the ability to notice tendencies, as I feel Nagy's worst aspect of his playcalling is the inability to set plays up based on previous play calls, defensive tendencies, etc. A guy that has "been there before" could really have a lot of value, even if not calling plays...though i believe Nagy would give up playcalling if the right OC comes along. Pat Schurmur is the most interesting possibility to me. If he doesn't survive with the Giants (and this is his 2nd stint of back-to-back sub 6-win seasons as a HC), then he has experience and ties to Nagy. As for up and comers, Mike Kafka, Chiefs QB coach comes to mind. Other than that, not too familiar with names. Maybe Freddie Kitchens if he doesn't survive in Cleveland. I'm hoping for Shurmur as OC and playcaller. I don't know how a high quality coach would want to come into a lame duck situation combined with a HC who calls the plays.