I do see the point you're trying to make with this proposal and I wrote quite a lot on this topic already:
- https://steempeak.com/steem/@therealwolf/on-the-need-of-downvotes-and-their-negative-consequences
- https://steempeak.com/steem/@therealwolf/clash-of-steem
- https://steempeak.com/steem/@therealwolf/one-currency-to-unite-them-all-71ooesyu
Or to sum it up a bit: having a global rewards pool does require downvotes, but they're very much subjective and awful for the person receiving them. With your proposal, I don't think that everyone will actually take part in this agreement since there is no code which is enforcing people to abide by these rules. Nevertheless, I do think this is a serious problem.