Alright.
The thing with this Bernard theory is that we're already seeing a clear and compelling motivation for his character unfold. We know he's dealt with loss - both from his child dying and his wife leaving him afterwards. We know that he's invested in creating true consciousness, true sentience in the hosts. Ford hints that he suspects the latter is due to the prior, which is likely correct. Bernard sees an ambitious, though potentially dangerous progression for hosts that at least partly encompasses "replacements". Basically, he's kind of a more fleshed out version of Professor Allen Hobby, William Hurt's character from A.I. Artificial Intelligence (more people need to go back and give that movie another chance by the way). He also directly serves as Ford's foil when it comes to what the hosts are and what they could be.
Bernard suddenly being a host throws out all of that and replaces his arc with the far less compelling story of a robot that didn't know it wasn't human. I say far less compelling, as that's already half of the cast. In particular, Maeve's arc, which seems to center around her discovering her lack of humanity and coming to terms with that - we don't need it again with Bernard. And then of course we'll see Dolores develop along her own path to "enlightenment" as the show continues, and presumably many other hosts coming to terms with who the really are.
Bernard being a host doesn't really add anything to the show, but rather takes away from it, and serves no real compelling purpose.
