I really love that remix. Feels really like something that´d go well with a desert.
The desert will probably be the place for a gym-battle against Titania I think, but then again
it´d be perfect for a battle against Solaris. I mean we haven´t seen his whole team, but so far it looked like something that would have an advantage in a sandstorm and a desert-field. The meteors are probably behind the derailing trains and the destroyed tracks.
Gible will probably be obtainable there, but as many others said here: Endgame. Probably with Rock Climb or something. Either that or it´ll be in an area you can access only after completing the game, because we can´t have nice things.
I really hope the desert will be a big area, not just small passageways or something. For all I care it can be a pain in the ass with difficult wild pokemon, Excadrill and Sandslash with Sand Rush everywhere so you can´t run. I mean it´s supposed to be a desert, and as that old man at the gate said, not a place for humans.