Since this is dealing with post-game stuff, I'm going to move this on over to a thread that already has this stuff covered.
I'd love to have another Red-type boss to battle post-game though. It would be even better if they could incorporate some sort of small plot leading up to that final battle as well. In HG/SS, you had to beat the Kanto Gym Leaders first and then travel up Mt. Silver. I would hope they follow something similar with this rather than make it too easy to find such a person in the games.