I think this is a terrible idea that does nothing but steal value from BTS bulls (people who hold BTS), and give it to BTS bears (people who hold bitUSD instead of BTS).
This will not achieve the goals you want of encouraging bitasset adoption, rather it will reduce the incentive to hold BTS, reduce the value of BTS, take money away from bulls and give it to bears.
In addition, it goes against the free market principles that Bitshares claims to believe in.
What we need is to create a bond/margin trading market, and then allow people to loan BTS/bitAssets to others for margin trading purposes, like you can do at poloniex. Then rather than the yield being a theft from one party to another, it is deriving from legitimate use and its rate is set by the free market. This would increase the value and usefulness and liquidity of BTS and nitAssets, rather than reduce it.