I have a suggestion regarding the swaps.

The issue: Borrowers mostly want 30 days, while many lenders prefer to lend shorter periods. Since the orderbook is shared, sometimes the bid/ask spread looks ...interesting.

A solution: Enable swaps trading. So, the same account could both borrow and lend, and would pay fees according to his net position. This would fix the spread, as it would become profitable to borrow short term (at a lower rate), and lend those very same funds for 30 days (at a higher rate). In this way, the swaps themselves would become a tradeable commodity. In the present situation they are only half way tradeable; you either borrow or lend, not both. Bitfinex would naturally need to ensure those swap term-arbitrageurs could cover their potential losses (i.e. the net position needs to be in proportion to the account's funds).

Bitfinex would benefit from the increased volume; short-term lenders would find a borrower quicker (while getting a better rate); long-term borrowers would find a lender quicker (getting a better rate, too). In general, the swaps market would work more smoothly.

Sorry if this idea has been presented before by someone else. I do not have time to read all those 278 pages.