i know everyone is expecting a cave update, but imagine if there was an ice update. there could be penguins which lay eggs similarly to the turtles or a walrus. i doubt anyone would be expecting this update, but it would bring a lot more use to snow / ice biomes.
ice on mountains
A new type of structure which is found in an ice cave or snow/ ice biome. the structure could be like an abandoned camp, and rarely you could find a villager or wondering trader.
The nearest update to come is Mountain Update.
Ice on mountaintops - alright, sounds good and cohesive.
Pengiuns have too complicated life cycle for minecraft biome system for my taste (everything we got now is restricted to contents of one biome, no inter-biome cycles).
Frozen ore, ice caves, frost - wut? What are you talking about?
Abandoned structure with villager inside in mid of tundra... it sounds all too familiar to me.