There is absolutely no reason for Pokemon to stop, not now, and not in the forseeable future.
First of all, if you don't like the new pokemon, fine, that's your opinion. But me, and quite a lot of others, like them alot. If anything, I think this newest batch might be the best in awhile, as they really remind me of the first generation of pokemon.
Second, pokemon never changes? Are you high? Pokemon has come a LONG way since Red and Blue. Sure, it might not look that way if you play every game in the series as they come out, but lets have a little test. I want anyone who says that pokemon hasn't changed to go and play Pokemon Platinum for no less than 5 hours. Done that? Good.
Now, I want you to go back and play Pokemon Red for no less than 5 hours. Done that? Good. Get it now? Pokemon has changed DRASTICALLY since the original. Sure, the very basic formula remains the same, but pretty much everything else has had a complete overhaul. Battle systems, type matchups, hold items, berries, abilities, the list goes on. Saying Pokemon Black and White are no different than Red and Blue is like saying that Super Mario Galaxy is the same as Super Mario Bros, just because they're both platformers.