Why don't you think it's a good idea?
I can't give you constructive criticism until I see the project, but well, I'll say what I want to say.
1. The Enderdragon. No.
Just don't kill the Enderdragon. You must not EVER TOUCH THE ENDERDRAGON!
Ahem.
2. Quests on various worlds would be nice, but do you really need various worlds? I think one bigger would be better.
3. Meh I'm just in bad mood