A lot goes into solving the optimization problems without invoking the scoring function a trillion times (which would entirely prohibit self improvement).

Look at where similar kind of framework got us, the homo sapiens. We were minding our business evolving, maximizing own fitness, which was the all we could do. We were self improving (the output being next generation's us). Now there's talk of Large Hadron Collider destroying the world. It probably won't, of course, but we're pretty well going along the bothersome path. We also started as a pretty stupid seed AI, a bunch of monkeys. Scratch that, as unicellular life.