While that might be worth experimenting, there's a high cost to it. Having high selection standards makes the network (YC's or any other) exponentially more valuable to those already in it. If you add a few not-so-good apples by mistake, there's no going back.
Also, you have to consider how much quantitative and qualitative experience YC has accumulated, the partners are pretty good at telling in a couple minutes conversation if you're a strong founder. This advantage would be lost with blind interviews.
