UPDATE: Nintendo has removed the listing from the eShop in the last 30 minutes or so; either the listing was a mistake because Wario's not in the game, or it's a mistake because they weren't supposed to say he's in the game.
It appears that Wario will be returning in the upcoming Smash Bros. games, according to the 3DS eShop.
Every week, the eShop has different categories that highlight specific franchises, characters, and more; this week, the 3DS eShop is highlighting Wario. In Wario's category, there are plenty of downloadable games that Wario is in, including Mario Kart 7 and Wario Land 3. At the end of the list, there's a little game called Super Smash Bros. for 3DS; this seems to suggest that Wario will be a character in Smash Bros. 3DS (and Smash Bros. Wii U, since they're both supposed to have the same characters).
What do you guys think? Are you hoping for the return of the Wario Waft?