Popularity issue persisting after 0.5 release

You mean because of the lack of sourcecode?
This is easy, put a README on it and declare why the source should be got fresh from the Internet, beside the Space requirements ...

The DVD can be distributed with the source. Was mostly thinking of magazines being commercial, which could be interpreted as using Xonotic commercially to some point. That might be a problem, if not decided upon clearly.

One thing that I think might help is to have that tutorial level from the beginning of the Nexuiz 2.5 Campaign in Xonotic's Campaign too.

That way new players can understand the mechanic's of the game a lot better than trying to learn it while being fragged by other players.

Is there anyway to adapt that level from Nexuiz into Xonotic?

I was planning to make a new tutorial level at some point, since I didn't find the map in Nexuiz very high quality. But sure, such a thing would eventually be needed IMO, and a tutorial map is very important for new players.

A big problem here is that most new players don't play the singleplayer campaign. They run the game and join a server. Then they get 0wned and ragequit. It took me a bit to realize that most the new players I was encountering weren't nexuiz players that had transfered–they were actually new.

So now when I'm idling on a public and someone new comes on, I play laser only against them till I find out how good they are.

I think it's logical not to join any server if you're new and don't know how to play well. That feels a bit silly to me, especially getting upset if you join somewhere and can't play well. But that is indeed a nice and considerate thing to do, and would help if everyone else did it.

One thing I notice on this matter, is the lack of a beginner's server. In Nexuiz, there was something called "DCC - Beginners server", where I first joined myself when I found Nexuiz. Might be helpful for Xonotic to have that too.