mhm... Contemplating doing the White 2 post-Elite 4 content.. I know there's quite a bit... will it give me any benefit for X/Y? Anything specifically you'd recommend doing to prepare for X/Y?
We don't even know if you'll be able to trade anything to it. Assuming we can:
Stock up on vitamins and held items from the world tournament.
Catch any of the Unova legends you haven't gotten to yet, since those are going to be the least likely to reappear. (Hell, catch all of them if you can, but those in particular are important.)
Make sure to put your lucky eggs, Rare and high-selling items onto your pokemon for transfer.
Nickname your Unova pokemon unless you plan on Breeding them in XY.
Delete Any HM moves on all your pokemon and get HM slaves you know you're not going to transfer.