I'm just imagining riding all the native Hoenn Pokémon and laughing at Luvdisc. Anyway, I bet we'll see it back again in some areas.
This sounds like it could be really possible, but...ouch. Those volcanoes, and not to mention Camerupt has a serious case of Magma Armour going on!
That said, I really hope we see more than the typical quadruped riding we're used to from XY. I'd rather see some flying or running. Dodrio racing was popular in Kanto in the anime, so something like riding one of them during a competition could be pretty awesome post-national dex.