I'd love to see a mod that - like EpicQuestz said - innovates the way you play, but maybe not in quite the same way that they meant. I'd really like a gamemode that genuinely challenges you to survive. "Survival" mode is great fun and all, but it's very easy to become self-sufficient. A mod that makes surviving a genuine challenge is something that would really excite me. I'm thinking along the lines of the game Don't Starve. In this hypothetical gamemode, farming would be both difficult and expensive, hunger can kill you quite easily, you need to drink as well as eat, monsters are more difficult to kill, resources more scarce, there would be environmental dangers such as extreme heat or cold, etc., etc. I know that's asking a lot, but I think that's something that a lot of people, including myself, would really enjoy.
