It's certainly decent. If a program is small (or the number of research faculty is small), they may not accept _anyone_. This means that past a certain point in the rankings, schools may have highly variable entering class--often based on how many people are leaving and how much funding is coming in, both of which can be highly variable. CUNY is probably a step above this level, and has a greater need for TA's than the other schools you mentioned. I'm not surprised you got accepted to CUNY, and attribute the rejections from the 'lower ranked' schools to those schools not really looking for students, at least with your specific interests.