It's not a "space" problem, it's a "resource" problem. And by "resource," I mean "editors who aren't hacks."
The people who think that every band, book, cheap fanzine, crappy website, and local celebrity need Wikipedia entries are mostly drive-by hacks. They create a crappy entry about a couple of things, then disappear until somebody tries to delete it, and then whine about how Wikipedia should include everything in the world. Those people aren't really helping anybody -- they're wasting the time of people who cold be working on entries that actually worth reading.
You know what "non-notable" really means? It means "this entry isn't worth the time of a competent editor." Encyclopedia entries can't just be created, they have to maintained. The notability standards are there to keep Wikipedia from filling up with so much childish crap that the grown-ups can't mantain it. Pages about non-notable subjects usually turn into poorly-cited, overly-editorialized, marketing-dominated crap, because nobody has the time to maintain all the non-notable pages.
There's a lot of childish crap in the roleplaying entries, actually. Poorly-cited regurgitations of WOTC books, short-and-pointless entries about monster manuals that do nothing but list the monsters, and a lot stolen clip art (I had to help remove all that, actually, before I quit Wikipedia). The roleplaying articles in Wikipedia are actually some of the worst there. Being published by WOTC doesn't automatically make something important, guys.
People who think an encyclopedia is supposed to include everything in the world don't get it. That's creating an encyclopedia that lacks quality control because it's too big to be managed.