The battleground might get a "filler"(depending on which of the 97456 definitions of filler you use) ep about it, or else it could be used as a way to introduce Buck(who does own the place, despite being 13-ish) while adding in some gym leader cameos, but I can't see it being much more important than that.
Do I want it to be more important than I think it will be? Eh, I don't really care either way. Seeing GLs in the anime is always nice(especially since the writers are getting better and better at making them memorable characters), and it would be an excellent excuse to introduce Buck, but I can't see Ash doing much at the battleground since there's no way the writers will bother having him rematch more than one GL there(maybe two if they spring for a double battle gimmick. Which would be pretty cool if done right, come to think of it).