The parameter generation, in a non-interactive zero knowledge system is always going to be an issue, unless its created through a consensus..
Interactive would mean you'd need the other party to be online to redeem your input, so we're working on a way of sending your funds into infinity, where they will be redeemed from infinity.
At a base level there's always going to be some sort of mixing involved, whether its destroying/minting, or whether its using some sort of tokens, etc..
Interesting, glad to see alot of thought is going into it.
Zerocash seems to be the state of the art in cryptographics, and I don't think these guys will quit until the project has success.