I thought about the same in the past, but I guess one major problem is, that ram-dividers are often bugged. It's very difficult to prove the correctness of a score if you can't even trust CPU-Z-validations. Even if you know about this fact, you can be foold by yourself, if you forget to set the right strap and so on. If you consider, that almost every two weeks somebody shows a SPi 32M "world record" just by mixing up Wprime and Super Pi, I don't think we will see a fair competition there.
Another problem is, how much categories do we want to have? Think about FSB, GPU clock, VRAM, Shader-ALUs,...