Regarding the comments about a custom FreeBSD desktop environment: that is being developed already over at PC-BSD. I don't think it's the default yet, but it's packaged with the OS. I think it was called Lumina.
I always attributed this to Linuxisms, but in my experience regardless of the desktop environment that I install on FreeBSD, as soon as I install one, the reliability of the system drops noticeably. Meanwhile, when I install a Linux distribution with that same desktop environment, I have no problems. So, in that sense I think there is a great case for making a desktop environment for FreeBSD in order to improve stability for that set of users.
Also, a desktop environment serves to surface certain abilities and statistics to the user. Making a desktop environment is related to the questions of "What do you want the user to do?" and "What do you want the user to know about?". I think making something for FreeBSD from the ground up, we might answer those questions differently than with Linux. We might also be able to capitalize on different features of the OS or maybe the desktop environment would include utilities related to FreeBSD-specific features.
As for the argument that the the goal of FreeBSD is being a server so desktop environments are not important: I don't think makes a good case for not supporting a high quality desktop environment solution. Yes, if you were running it JUST as a live server, you probably wouldn't have the desktop environment. However, I think it's enormously valuable for a developer to develop on the platform they are developing for. I make a lot of server-based projects. My public-facing server doesn't run a desktop environment. However, my development/design/test machines are running servers so that I can test the project as I work. However, on my development machine, I certainly want a more human-optimized user interface whether it's because I find the window management more productive or whether it's because I want to preview in a browser what my users will see. Because of this, even if being a server is the absolute primary goal of FreeBSD, there is a good case for giving it the option of a strong desktop environment so that developers of server applications, developers of the OS itself, etc. will be likely to be running on it and relying on it on a day-to-day basis. This will lead to their applications being better and will probably also result in them developing on little side things as they find inconvenient tasks in the OS.
The argument against desktop support is circular. There are not enough users/developers to support a feature that will make us appealing to many more users/developers.
! Though I'm using now a minimalistic setup for its better configurability... but just to know that things are there is good. Thank you for the info.
