Cost vs Benefits of Wikiprojects
From my own experience, the real problem of WikiProjects is that most of them are essentially inactive. I do a lot of gnome work and when I spot problems that I can't solve, I try to notify the relevant project. That seemed like a pretty good strategy when I started but in most cases, it turns out to be a waste of time since project members either don't watch the talk page or don't actually respond to these requests. Writing GA and FA is nice of course, but it's equally important for a project to take routine care of its articles and to take on less glamorous tasks. It's symptomatic of a more general weakness of the project: there are very few mechanisms in place to report problems requiring the help of a competent editor.