My update wish list:
1. Vertical slabs. They will have to be added one day.
2. Wool slabs and maybe stairs too.
3. Sideways stairs
4.Monster spawner+ Giant mushroom blocks in creative inventory, I always forget their block ID.
5. Fix the lighting glitches, especially the one that makes your roof dark if it is made of slabs!!!
6. Make it possible to get jumping boost potions in the game and remove the fall damage from the jump (they exist in the code just unobtainable but you can put the effect on mobs with MCedit filters)
7. Make fire less prone to burning down your house.(I'm not sure but I think they might be adding a cheat for this.
8. Put the cheat: time minus in the game
9. Take out those really random screwed up looking trees. They look crappy and it takes me ages to remove them.
10. Change iron blocks back to their old texture and make bricks look less terrible.
11. Vertical string/tripwire
12. Fire arrows set things on fire but you can turn this off to avoid griefers
13. Redstone and Coal blocks
14. Vertical redstone.
15. Less buggy pistons
16. Stop spawing me on a tiny island in the middle of the ocean when I play survival/hardcore or at least give me a tree.
17. Make emerald ore more common.