Here's some ideas for Minecraft.

1: A social Minecraft site (Friends, Private messaging, follow/subscribe, etc)

2: Personalize!

3: Minecraft should have an easier way of making skins and texture packs.

4: Easier server making!

5: Add a new mob: Raccoons. If you drop a food item then they will head toward it and they can chew through blocks (not iron or cobblestone only wood) and take from furnaces (with food in it) and run back to their "hole" Raccoons can mate and have babies themselves. So a job on a server could be raccoon hunting. Also Raccoons cannot steal from chests. Lol they are just like griefers!

6: Giving a creeper gunpowder will make them go away, way far away. They will not be tamed.

7: Chairs/couches, you can sit in it during the day and the day will go on 5x as long. Also they are like fences (not 1.5 blocks high) they can connect. This could lead to some fancy houses.

8: If a baby dog and baby cat both live in the same house on Minecraft (about 60x60 blocks for mansions) The cat will not run away from the dog.

9: Dogs could automatically kill raccoons if they are tamed. No need to hit the raccoon.

10: On a server once, I was in a gate and the creeper was on the other side. It tried to come after me and it went to the gate (it was opened) when it got there it didn't care. If they get too far away (which is really short) They don't come after you. If creepers come after you and you run away far, they should at least have to look for you. Make it kind of inaccurate but able to at least be a little bit to the side/behind. It it comes in a 16 block distance when the creeper is looking for the player, It should come after him/her. Also the creeper starts looking for the player when it is out of a 50 block distance. It will not stop looking for you. It could make Minecraft scary, lol!