Anything by Junji Ito. We need genuinely good horror in anime. Shows like Another just do not cut it for me.
Also an actual dedicated adaptation of Negima with a decent animation budget.The half hearted attempts that were made to try and adapt it so far, be it Negima! or the even more inferior...
Soul Eater and Any anime involving Witches/magic users.
The DWMA are trained that Witches are evil and should be killed in order to make death weapons. They would automatically become the antagonists to any Witch/Magic User anime. It would be quite interesting to see how the two would fight...
Higurashi probably fits the bill. I will never claim it is the best anime ever, or that the animation is impeccable, anything like that. That said it is still one of my favorite anime hands down and one I've watched several times through without losing interest in it. I especially enjoy watching...