So I have a theory why Q hasn't appeared in a while. I know I'm living a pipe dream thinking this theory will silence the q-is-gone-concern-fags but, well, here it is:

At least twice (maybe 3 times?) Q has indicated we anons are more astute than originally thought and have affected or could affect Q/GEOTUS's timetable. Perhaps he is afraid our unmeasurable talents might disrupt things during a particularly sensitive part of the plan.