I'd much rather have a feature animated film about The Year of Rogue Dragons than a new D&D cartoon.
The D&D cartoon was pretty good, but I don't think it should be redone. They should focus on settings (an Eberron cartoon could be very good and I don't understand how we don't have a Drizzt series already).
I loved the D&D cartoon (and yes, Sheila was an illusionist in Brazil) but it's ran it's course. They should try new ideas.

TL;DR Adapt The Year of Rogue Dragons, Drizzt or Eberron into a cartoon series