Portfolio plans were introduced very prematurely. A lot of lenders will be burned on the early ones, I suspect.
The platform really doesn't need more tinkering; it does what it's supposed to do: match borrowers with lenders, and track the transactions. They're navel gazing, when they should be taking a broader market view. They should be anticipating opportunities, and potential dangers (multi-p2p site loan taking is one that comes to mind). They should be bolstering the bottom line of what they already have, with better service.
Prosper needs to grow its user base, and become a more robust presence in the P2P world. A year ago, Prosper was the first name in P2P lending; the pioneer. Now they're losing ground to lendingclub. I bet in a few years, lendingclub will be the first "name".
How to grow it is a complex issue; I do have some ideas on how not to grow it...