Okay I expect 2-4 new pokemon. I bet on the rodent and the bird, along with two key pokemon for the anime. If we're lucky they could also reveal the second evos of the starter, even thought it's too early. Also, probably we'll have details for Xerneas and Yveltal, such as typing and classification. I expect announcement of some key features like the 6 gen's cgear/poketch/pokegear/etc. And details on at least one new area, probably the first town/city. Finally, art for the trainers and the rival.