The discussion surrounding MPlayer2 was resurrected in the Phoronix Forums this past week. One Phoronix reader immediately jumped to say that "Mplayer2 is dead. Nothing new for 11 months now." and to also criticize the program for the lack of supporting the (outdated) MPEG-1 format.
While some may think it's dead, the MPlayer fork is still being actively developed. The Git commit log reflects a number of commits in the past week with many having already happened since the start of the new year. Among the commits going into MPlayer2 are libav updates, various fixes, screenshot support for X-Video/GL/VDPAU, Mac OS X 10.7 fixes, and various other items. There's been more than 100 commits going back to last summer. The MPlayer2 development mailing list though isn't particularly active and there's only a few active contributors to the forked code-base itself.
For those not familiar with MPlayer2, which was first brought up on Phoronix in March of last year, among its features are better multi-threading/SMP support for modern hardware, more advanced NVIDIA VDPAU (Video Decode and Presentation API for Unix) functionality, better Matroska file support, better pause handling, OSS4 volume control, and many other fixes and other changes. Some of the work is detailed on MPlayer2.org, but overall their project site is quite basic.
MPlayer2 is also still carrying plans for an official 2.0 release (the road-map), but at the moment they don't have any set date for this milestone or any future plans (MPlayer 2.1, 2.2, etc). You basically need to be building and running from MPlayer2 Git right now for best results.
Sadly, one of the major missing features from both versions of MPlayer right now is VA-API support.