Batman: The Animated Series worked pretty well in that they managed to incorporate somewhat mature themes into the show, with the stories feeling like they could actually fit into the world of the comics and films. The writing and animation had appeal that both kids and adults could appreciate.
This, on the other hand, doesn't seem like it wouldn't make any attempt at remotely fitting in with the source material. I can't see them having mature themes or sophisticated writing in a high school setting either. The concept art is rather nice, for what it is, but the idea as a whole just doesn't seem like it would work particularly well.
Oh, and isn't the Penguin a little old to be attending school with Harley Quinn? They should have made him a creepy principal or something.