Donations sounds like a really pants way to allow community map makers additional funds. If i'm honest, i feel most of the community made maps are broken or have aesthetic issues that should have been sorted before they became officialised. I'm not sure there's a single officialised map that i actually enjoy playing (although there are a couple that i don't have problems with, i just don't like the gameplay). But that's just me being a snob.
As much as i appreciate Valve's commitment to an author's original work making the cut, sometimes i wish there was an editing process that would go into an ammatuer map and fix up some of the inherent problems that come with the author's limited understanding at the time of X's maps construction; for the sake of the maps potential. Or at least have a little more commitment from the author's when it comes to improving an existing piece of work despite the fact they've already profited from it. Or maybe pride (in my work) is just my sin.
Still, it's better than nothing. I guess companies like Valve aren't willing to go that extra distance for community map makers and have left it to other community members to support each other. Maybe it'll work but i don't have faith in a system like that.