I know that when I've hired programmers I definitely weigh potential and willingness to learn more than experience. Sometimes when someone has experience they are really just stuck in the same old ways of doing things, and it becomes difficult with them to change the company culture or have the kind of momentum that you need. Surely the better VC's recognize that fresh blood often produces the very best results. Y-C does.
His criteria for the definition of A teams all seem to revolve around experience rather than talent. Experienced people probably already have some money, which means they have the potential to lose it, which means that they're likely to be more conservative. Being conservative means cutting both your standard deviation and your mean outcome. But VCs shouldn't be encouraging conservatism, because when you're running a fund, the law of large numbers kicks in and standard deviation doesn't really matter. It should be all about the mean.