I don't see it as Seth at all if the goal Roman is going baby-face. And really, Seth hasn't been a babyface all that long so I can't see him switching back to heel between now and '41. He's going to get a massive babyface reaction when he does return, as will Roman.
The problem with WWE right now is that most of their biggest names (and the guys who would be legit opponents at WM for Reigns) are suddenly fan favorites. Roman, Seth, Punk, Cody, KO, Orton, etc. After years of too many heels and not enough babyfaces, the roster is now overloaded with heroes and none appear ready to go heel.