I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
1. Characters are not developed enough.
2. The peaceful coexistence between vampires and humans is flawed, particularly in the execution of the Cross Academy and the Day Class/Night Class dichotomy.
3. It just doesn't move. I feel like I'm treading water reading this.
4. The tropes. Dear Primus, the tropes!
5. The angst. It's so thick and angsty it feels like it wants to choke me. Or makes me want to choke myself.
I do enjoy the art, even if it's not quite as sophisticated as the art in Loveless or FMA. I also compulsively read this, maybe because I don't take it seriously so it's a super-quick read.