I wish Jeb would add this, but obviously he won't. Ever.
1. Dual-Weilding with shields, like Notch was working on (apparently)
2. Red Dragon that is tameable and spawns in the overworld.
3. THE ENDER DRAGON EGG STILL HAS NO USE AT ALL!
4. More fricken mobs, like fish in water (planned, but not gonna happen...)
5. LANTERNS
6. Sky Dimension (Why did they replace it? The End is cool and all, but the Sky Dimension sounded better).
7. The Wither is IMPOSSIBLE to kill, and when he drops the Nether Star, it's used to create a Beacon, which in my opinion is 100% not worth it at all! Make something better for the Wither to drop!
8. Wither Dimension! Building him like an Iron Golem is lame.
9. MODDING API
10. Better performance.
11. Place-Able Pumpkin Pie (Like cake)
12. Furniture!
13. Other Emerald uses (something cooler than Emerald armor and tools)
14. Better weapons, or more weapons (like, for example, The Ender's Tooth, or something like that, that are really powerful and are meant for killing bosses).
That basically wraps up what I want for 1.5, but as we all know 1.5 will just be lighting fixes and stuff like that.