Here is some things i would like.
1. If your on hard there is a 3 percent chance you will become a zombie and all the passive mobs would come and trample you, the last part doesn't have to be added
2. A feature where you could change your username. some peoples usernames are horrible like mine smith53789.
3. An in game server list.
4. A join random server choice. where it picks a random server. as you can probably see i have trouble finding good servers.
5. zombie pigmen villages in the nether.
6. overdosing on potions, if you drink the potion too much it gives you a bad effect.if it already is a bad potion like weakness etc. you will get the poison effect you get from spiders.
please tell me what you think about these number 1 might be hard. but the rest i think are cool.