The biggest one for me is probably poor pacing. When an arc gets overly stretched out it can really kill the enjoyment even when the story and characters are strong.
Also, not enough people of color. Yep, I'm gonna be "that guy," he was bound to show up sooner or later so don't act surprised. :p
It's not a big deal and I'll live without it, but having more diversity in anime would be nice, seeing as how anime is huge in the black community anyway. That's why I applaud shows like Cowboy Bebop that try to be inclusive.
I thought Asians were included in the term people of colour.