Most of these features would be added for building purposes, as I am a builder.

* More materials for building!
- Iron fences or railing, like cobblestone fences

- Something to make more realistic flags, like cloth that waves in the wind? (Could be crafted from string or wool...)
- More types of stone or metals or ores?

* Some sort of basic Vanilla server hosted by Minecraft themselves that players can use as their own server? This would take some work and thought obviously.

* Maybe more varieties of NPC villages
- More complicated buildings
- More complex villagers with more features

* More varieties of mobs and mob droppings, the more the better

* More plants; trees.

* More biomes

* Custom paintings and music

* Maybe some more smaller features like plates where you can put food on? Shelves that hold 3D items?

* Maybe a new realm even?

These are some features that would be cool if they were implemented into Minecraft.