While on the surface it sounds interesting, I'm not entirely convinced it's a good idea to allow villages to generate in every biome. Maybe limit this suggestion to just the snow biome, as that's the only one that has nothing overly unique to it. Houses can be made from spruce and snow blocks.
And just forget about Extreme hills! Those villages would be Messed Up! I mean, you've seen villages that generate on the edges of ravines and small hills in plains, right? Multiply that weirdness ten-fold.
From personal experiences, village spawning has been pretty spot on, in terms of how many per world, and the accuracy in which they are rendered into the terrain of the biome. I know this is more of a preference thing, rather than to increase the spawn chance of villages in a world, but I don't really think it's necessary.
Adding the same village template made of different materials native to the biome it resides in wouldn't really be adding anything to the game, besides structural scenery, and like Deskepticon said, it would only really impact the snow biomes as the materials houses are built from would be drastically different to other villages.
I'm all for new building and villager types however, being able to offer a wider variety of profession-based trades, and showing a little more variety in the village composition.
We have enough villages on average as is...and sometimes even too many. Can you imagine how many village there'd be if they appeared in pretty much every biome? It would become redundantly annoying very fast. Also, I've seen extreme hill and jungle villages. They look really bad and stupid.
this might sound like something that could happen on the PC since the game is technically infinite and villages are very spread out and rare to find but because you are extremely limited on consoles and tablets I don't think it would happen.
I thought I read a rumor that Mojang were going to add snow villages in 1.9... but I could be waay off base.
I think it would be neat if they did expand the types of villages to match some different biomes. I think this could be done without increasing the frequency of village generation. I agree that game-generated villages don't come out right in hilly biomes, so I think I would limit the idea to two biomes: tundra and savannah. Yes, I know that villages do generate in savannah biomes now, but I'm thinking they could be styled a little differently than the plains ones.