A few reasonable suggestions:
-Maybe add NPCs
-Blocks drop materials(Break a sand block and get a sand material etc)
-Craft table(You have to take materials to make weapons and objects)
-Night and day system
-Health?
-Have to obtain all material.
I hope you have some of that planned, I Honestly can't wait for more of this homebrew. It deserves more fame than what's been given. I don't like Lua games, but this has just hit the spot. I can't say good job any more than I am now.

[/spoiler]