What's the point of a tundra / desert if you can't get lost in them? They should stretch as far as the eye can see, and much further.
We also need oceans, but that's another matter.
Right now I'm working on a little color face-lift for the biome textures.
Wow, that looks really great.
I really don't have much of a problem with the textures right now, but I used to use Painterly and I know I'm going to get sick of them soon. I don't think I would get bored with something like yours.
My biggest problem with the biomes is how tiny they are, especially the desert. I was planning on making a desert "doom tower" out of the basic hellstone, but it kind of ruins the effect if you can see the snowy tundra from the top floor, even if the building is smack dab in the middle of the desert.
Going beyond that, my biggest issue with the update is the leaves not decaying. I really don't feel like whacking every single leaf block from my 64 tree farm just to get a stack of saplings, so I just can't get back into the game until that's fixed.
I like the fact that there are greener and duller grass and tree colors now. They really add to the game. I do however feel that the default (as in areas that were previously explored) should have been set to the forest temperature/humidity so that peoples existing bases have 'nice' colored grass.
I also agree that biomes could easily be doubled or tripled in size. As long as you can cross a Biome in 3 days (2 nights) I am happy. Just makes the Nether more interesting, as exploring different biomes would be easier using the nether as oppose to running on foot.