I agree with you. The error in most crypto is the reward, which gives rise to strategies that do not necessarily induce the desired properties. I also think that the only viable kind of crypto currency is where the validation/consensus decision is taken on a voluntary basis, the "reward" being that the system in which you are invested, keeps running correctly.
However, you still need a kind of deterministic decision *that is hard to game* (because you can do "proof of work" like calculations to get the deterministic solution in your advantage). This is why a kind of PoS signature scheme is necessary in my opinion.
One alternative incentive scheme might look like this:
- Nodes have to do certain tasks in order to stay alive. In my Proof-of-Membership proposal for example, minting accounts are required to make "heartbeat" transactions every now and then, otherwise the accounts are downgraded and lose their priviledge (interest rate that is paid with every block built by anyone).
- Now, running a node the whole time (or turning it on regularly) will be tedious to most end-users. That's why you can offer them as a block reward the the temporary or permament exemption from their obligation do make heartbeats.
Such a reward mechanism there's no incentive to own multiple accounts as users are trying to get emancipated from hearbeating as soon as possible.