Remember all those kids shows growing up when the evil teacher would get replaced/quit/be sick etc; and the kids would cheer because they'd SURELY get something better? But instead were greeted with a substitute even worse? Then the kids would get the OG teacher back who would save them, and realize that they're only like that because they cared about them?
That's kinda how I feel about Cena. Sure, he's killed every talent on the roster, but at least he can talk and put on a good match when he wants to try. Roman is only going to make the Cena years look better in retrospect. That is how dire Roman is.