There's going to be about 300 Pokemon pre-Elite 4, that's the biggest Regional Dex yet and double the amount in B/W.
The new Challenge Key apparently raises trainer's AI, not just their stats. It should be interesting.
I never played Emerald, so I'm not entirely sure how the Battle Frontier worked. Still, the World Tournament should give 5th gen some much needed endgame.
I agree it's just a cash-grab, but at least they're trying to make some improvements and not just rehashing it entirely.