Why Not Creative Commons with a Caveat?

I realize the whole point is to get a lot of free content out there, especially content that can be mashed up, but why won’t Creative Commons provide an option along the lines of this: Write to me and tell me what you want to do with my music. If I like it, you can do so immediately. If I don’t like what you want to do, you can still do it, but you will have to wait six months. Or, perhaps, you will have to go through six rounds of arguing back and forth with me about it, but then you can...