The X.Org development community was relatively on time with their Beta 1, Beta 2, and Beta 3 releases, but all work has virtually seized since that point. The first release candidate was supposed to be out before Christmas but that never happened and we have yet to see any release candidate even weeks later.
Nothing has been committed to the server-1.6-branch of the X Server Git repository since the 16th of December. The X Server 1.6 tracking bug has ten open bugs (of 17 total).
The sad reality though is that this setback shouldn't be surprising considering the numerous delays that have plagued the X.Org camp in recent times. X Server 1.4.1, which was a bug-fix update for X.Org 7.3, was released 212 days late. Most recently, X.Org 7.4 / X Server 1.5 was released months late. The list of other delays and problems continues on.
The X.Org developers are stretched very thin, but recently they have had the added burden of handling some invasive changes such as the Graphics Execution Manager for providing GPU memory management within the kernel, several revisions of DRI2, drivers turning to kernel mode-setting, and other radical work.
X.Org 7.5 was talked about for an April 1st release but nothing has yet amounted when it comes to even a release schedule and planning.
When the release of X Server 1.6 does occur, which we hope is just weeks away, it will introduce RandR 1.3, X Input 1.5 with device properties, Predictable Pointer Acceleration, and Direct Rendering Infrastructure 2.