I was also annoyed that only Twinleaf Town, Route 201, and Lake Verity had any snow. I also still hate the route before Snowpoint a lot, it adds nothing to the game play experience whatsoever, and is incredibly annoying. Maybe they could have put in an item like "snowshoes" that would allow you to walk over the snow with out a problem.
Distortion World was not nearly as cool as I thought it would be. It was a very lazy attempt to show off the DS's 3D capabilities. It would have been cooler if it was more like the real world (trees, grass, mountains, maybe even Pokemon) just the physics were tweaked so you knew you were someplace strange.
All in all, it could have been a lot better, but it still is a fun game.