Changing seasons could make it take longer to complete 100% of all quests, which is something I'm in favor of. It could also provide some extra strategy (such as fire elementals being stronger in summer, but weaker in winter, so be careful what you summon) to the game.
But I doubt it will make it in, and if it does, then it will probably cost us climate changes based on latitude. Money and time are limited, after all.
I like the wait/rest systems of TES and Arcanum more then IE's "8 hours rest," but I think that was more due to the source material (D&D) then the design team.
Aside from that, I think if the IE games had it, it'll probably make it in, if not, I can only hope it'll make it in. Time-based mechanics are always cool.