Mesa 7.2 has just under a dozen official fixes and it also adds 3D acceleration support for the new lower-end Intel G41 Chipset. The Mesa 7.1 release had support for the original DRI2 (Direct Rendering Infrastructure 2) implementation, but that has been stripped out of the 7.2 release. DRI2 was recently reworked and the 3D bits will now not appear in Mesa until the 7.3/7.4 release. Mesa 7.2 also doesn't support Intel's Graphics Execution Manager, which is their new kernel memory manager replacement for Tungsten's TTM.
The release notes for Mesa 7.2 can be read here.