I'll pass, but before I do you might as well know why:
1. I like the idea, nothing wrong here. From your post I thought it was a large mod or something.
2. Not sure what you mean by "item creation," but this doesn't sound good. It sounds like you'll be feeding devs ideas, but this isn't always such a bad thing (I'll explain in the next point).
3. When you start paying people for their work, you're running a business. Anyone looking to join your business (or take you on as a client) will want to know when they're getting paid, how much they're getting paid, etc, which constitutes a legal contract. The terms you've laid out here are not rigid, and they provide room for you to screw me by saying something like "you wrote this cool mod I asked for but it doesn't have this feature, so I'm not paying you." I don't want to take this risk.
4. The main issue though is that I have my own ideas which I would like to work on in the meantime. Feel free to use any of my mods on your server and I wish you the best of luck.
