Yeah I read that, and it's not surprising. What's also not surprising, however, is that the Free drivers, while slower and having fewer features, are more stable and reliable.
It seems to me that if the card were architected as you say you would like, you might indeed get the performance of the proprietary drivers while still using a Free shim. But you would also get the instability, and there would be absolutely no way you could fix it except to get new hardware. So it doesnt seem like an improvement to me, quite the opposite. With my ATI hardware, I at least have a choice.
I would love to have Free drivers that were stable and reliable and also supported the full feature set and ran as fast or faster than the blobs - that's what we should expect, frankly, but I know we arent getting it right now. Free drivers that are stable predictable reliable at least give me the opportunity to use the ATI hardware in my system without the bugginess of the proprietary driver, at some cost. If it were architected like the pi, it sounds like I would no longer have that option, whatever binary buginess it has will be found in the GPU, which you have no access to, but which by contrast can corrupt or deliberately overwrite anything you do with the ARM chip.