The RAMBUS speed is the main issue. The RDP can literally be stalled over 70% of the time waiting for memory. It's extremely flawed.

They could have used SDRAM and it would perform so much better, and I believe the cost is around the same.

If you wanted to cut something, cut the antialiasing. While very cool, it is a bit wasted on CRTs. Worst of all, for some reason they have this blur filter which smears the picture horizontally. Luckily it can be deblured by appliying the inverse operation.