Seriously, there are some AMAZING encyclopedias which consist of material that is 99% unsuitable for inclusion in Wikipedia. I'm thinking of things like snopes, tvtropes. etc...
The community that cares about DWM, FVWM, Compiz, lwm wm, xwm (all of which I've used at one point or another, and, only half of which are currently in wikipedia) should do likewise, create their WM Encyclopedia - (wmipedia? wmtrove?) and just tell wikipedia to go stuff it.
The question as to where to draw the line is a little gray - I _personally_ think that all widely deployed (That is, more than a couple thousand users) systems like Window Managers, Linux Distros, Applications, should have a home on wikipedia - My home town of Lumby only has a population of 1800 people, and it managed to get an article - why is a window manager that is home to 10s of thousands of people any less notable?
I think every release of Linus's linux kernel should have its own page on wikipedia. (Check out "http://kernelnewbies.org/LinuxChanges and tell me that each release isn't notable).
My only requirement is that it have _some_ breadth of interest beyond the author who writes the article, and that the material maintain a high level of quality, NPOV, and citation.
But, I'm clearly one of those lumped in the "Inclusionist" world - which is clearly a direction the English Wikipedia is not going.