The only problem is the number of questions per day which I believe is caused by remaining a long time in beta phase. See also the site stats:
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As an occasional user on GL&U, I've wondered the same thing from time to time.
IMHO the one statistic that needs improvement is the most important. 3 questions per day is just not even close to getting it done. There aren't enough questions popping up to justify frequent visits, and since so few total questions have been asked (about 1000) there isn't that much content available for prospective users to peruse.
Hopefully we can get this turned around!
Graduation is not decided solely based on those statistics you see, there are other factors the SE team evaluates when deciding whether to graduate a site or not.
One important one that I have seen mentioned a few times on different beta sites is that they look for a steady upwards trend in traffic. The traffic of GL&U looks more like it's going sideways at the moment, so that might be a factor that is hindering graduation.