Complex characterization, yes, but not complex stories, at least not in the vein of She-Ra or YJ. MLP:FIM and DCSHG were very similar shows tone-wise, with SHG having more multi-episode arcs
Also it’s overly simplistic to call Harley Quinn a villain in the show, as every single one of her appearance hammered (heh) us with the fact that she and Barbara were best friends who really truly did care for eachother.