Seasons

Instead of just making a new biome to represent each real-life season, why not just make a few temperate biomes (possibly even out of existing ones)?  Some biomes would remain the same as they always are, while others, like the forest or plains biome, could change seasons either on some sort of timer (changeable by a command) or as the real-life seasons change. Personally, and I'm sure others would agree, I think this would make Minecraft feel so much more alive.