I really, REALLY want more water Pokemon that aren't fish/reptile inspired. A water Pokemon that is inspired by an animal that you wouldn't associate with water. A water-cat would be awesome. I think it is almost required to have a decent water Pokemon on your in-game team. If you didn't get Oshawott in B/W, you pretty much could have the creepy Ghost/Water thing or Swanna. More water choices will be awesome.
I love the dual types they came up last gen, and I'm hoping for more. Ghost/Fire is awesome. I almost want an evolution for Ninetales, being Fire-Ghost.. But then I think of how many ways it could go wrong, so I think "..Naw.." you know? Anyhow.
We don't need many grass or bug types with what was introduced last gen.
MORE COOL POISON TYPES! Less dual grass/poison and bug/poison.