Who is everyone who doesn't want them to move away from Reeves and why is Snyder the only other alternative? The character shouldn't be pigeonholed that way. Rejection of Snyder is not proof that people have trouble letting go of Reeves.
Superman Returns is heavily criticized for being a Reeves rehash. This is not news. Both Returns and Mos/the DCEU are flawed movies and that's why they haven't been embraced. Cavill could be replaced tomorrow and the reaction wouldn't be that severe, not the way it would be if Gal Gadot was replaced as Wonder Woman.
Then maybe Nolan wasn't the best creative mind for Superman, just because he was good with Batman doesn't mean we can just blindly apply him to Superman. Even so, it may have been a more solid movie with the most controversial and needless element (Zod's death) removed from it.