A similar thing happened with the Intel drivers transition away from multiple independent drivers to a unified memory management model.
It came in stages, one after a while, and performance and stability suffered. KMS, GEM, UXA, etc etc. One feature after another.
Then you ended up with the low-point of reliability and performance when you had the Xorg driver that supported all the different combination of legacy and next-gen features. You could choose to go with the older stuff and get better performance in the benchmarks, or go with the newer stuff and get better usability with composited desktops.
Now, finally, with Fedora 12 the Intel drivers dropped the support for the legacy stuff and now rely entirely on KMS, UXA, and GEM all being functional. Now you have Phoronix articles praising the performance of F12 isntead of trying to account for the loss of performance in different Ubuntu versions.
Hopefully with the Radeon stuff they will take a more aggressive approach and thus shorten the time that users must suffer through the transition period, but I don't know how practical that will be considering the restricted resources in terms of time and manpower that goes on with typical X development stuff. The faster they can move to the unified memory management and get away from relying on the DDX for everything the faster they can concentrate on improving performance and application/game compatibility and introducing Gallium features.
And, yes, cheers to the developers. Everybody needs this stuff to work and I know it is hard work. Thank you.