CF1994 said:
-Access to another area of the Safari Zone, assuming that will return in ORAS, where you can find mons not in the Hoenn Dex. This would be a good time to make mons that have unavailable Hidden Abilities available if Friend Safari does not make a comeback. (I am referring to the likes of Skrelp and Dragalge and their potentially useful Hidden Ability, Adaptability.)
As far as undistributed Hidden Abilities go, I think they'll probably save the 6th gen HAs for the next Kalos game, but they'll probably have some in this game. I'm thinking it'll go like this:
ORAS: 2nd gen starters, 3rd gen starters, 4th gen starters
Kalos: 5th gen starters, Tyrunt, Amaura, Skrelp
CF1994 said:
-Make the Scorched Slab area be a hideout for the likes of the Legendary Beasts and/or the Lake Trio, depending on your Starter.
Volcarona would make more sense. I'd want to put it in the main game, but no expanded Hoenn Dex.
CF1994 said:
-Steven Stone will have a Beldum available for us in Mossdeep City after beating him and the Elite Four. It probably won't have its' Mega Stone, though.
Where would you get it then? I doubt it'll be event exclusive.