This seems like an odd thing to ask here, given it is questions for the dev team, and at least Ame, Inuki and Dan would know. If you want to discuss it with other members who aren't in a dev team, this thread works better. However, if you're just interested in what those of us who are in a dev team but aren't in the know think, never mind
I personally think that we won't see this field until the E4 (or if we do it won't be in a gym battle- it will be in a random outdoor environment). I think it could used by Laura or Bennett depending on which one is in the elite 4.