The lobby has been included with all Xt builds, though it was only activated by a cmdline option. Part of the reason for it being disabled by default is that it's more interface work for modders since those would be required artwork. If the art wasn't there then you would be unable to play any multi at all (with FS2NetD at least, only direct-connect would be usable). Another part of it is that the lobby had a tendency to die on people, either crashing the game outright, killing off the window and leaving the process running, or something similar. The banner support was part of the problem, so that code has been temporarily disabled on all platforms, and another part was just some porting issues that should be totally resolved in the 2/15 build. So, the cmdline option was removed and now the lobby screen is always used when PXO/FS2NetD is enabled.
The 2/15 build isn't really something you want to give out, unless you are really testing multi and the lobby code. The lobby code in particular needs a ton of testing (I found it amazingly difficult to test IRC related issues with just one person

). Otherwise the 2/15 build really shouldn't be used by anyone that values their pilot files, scripting support, or various other things. I've already fixed several bugs since that build was released, and that wasn't even 24 hours ago.
But with the server crash still not being identified yet it would probably be better to use a 3.6.9 build for any real multi play for the time being. We do need it heavily tested, but the crash makes server stability/availability highly suspect.
And regarding the shader issues Shade, you do have the shader pack, right? The shaders are included with the 10/28 build, but I rewrote the code and shaders from scratch after that and the shaders can no longer be included in the build itself. The newer code also checks for a couple of special NV and ATI extensions to know if your hardware supports SM3.0, in order for the shader code to actually work. The log from a debug build should identify the problem though.