A month later at the X Developers' Summit, Keith Packard had clarified his UXA work. At that time he said the information learned from UXA would work its way back into EXA by separating the pixmap management and acceleration components of EXA. At that point, UXA would then die off. However, now it appears that will not be the case.
From today's X.Org @ FOSDEM talks it sounds as if UXA will simply live on and be its own 2D acceleration architecture. There are plans by Intel on moving UXA from living within the xf86-video-intel driver and pushing it into a future X Server release.
We previously shared UXA benchmarks showing the advantages of this new GEM-based architecture. We will have more information once our X.Org recordings have been uploaded.