We cannot drop btcmine for having lower efficiency than other pools. Being a score-based pool, it provides an important role - a baseline expected utility of about 90%. All the times you are mining in btcmine at 90% utility, all the other pools have utilities much lower than that - you would lose more by removing btcmine from rotation. Btcmine also has a very good response rate, so it often fills in extra getworks when a higher-utility pool cannot keep up. Notice that for most rounds in btcmine, the expected utility actually is just about or slightly higher than 100%. Unless you can show with statistical significance that the actual btcmine rewards, and therefore efficiency, are lower than the predicted utility, it has to stay.

An even better alternative would be a constant-utility pool like Continuum, but I am afraid whether doubling its hashrate is such a good idea. Continuum is a good fallback for solo hoppers, but we, as a pool of comparable size, would not gain much decrease in block finding variance by joining up. We would be better off generating our own getworks, which, by definition, have expected utility of 100%... Perhaps I'll increase the priority of generated getworks over pools with utilities below 100% (right now solo getworks only get used as a fallback to keep the work queue running).