Well, I think that a metroidvania is the closest we will ever get to a CVRPG. That being said, that doesn't mean a RPG can't be done. I could see creating a character. choosing a class (belmont, belnades, danasty) each with its own skill set. You choose said characters development. Different locations. Open world.
Yes, I know this sounds like elder scrolls, which has no platforming, but the different locations (demonic castles, graveyards, swamps, evil churches, etc.) can be in traditional CV fashion with platforming and enemies. In the 3rd person from behind in 3D or from the side in 2D makes no difference.
I just feels that it has potential if done right. Just no MMOs. CV heroes are meant to do things solo.