What went wrong?

Been watching through all the DC animated movies, and I can't remember the last time I saw one that was less than good. This one though is just bad, shockingly bad really. Sloppy character work, sloppy animation, ugly art-style, it's like it was made by a completely different studio. I really hope this one is an outlier and not a sign of things to come. The characters act in non-sensical ways, much is left unexplained, it's riddled with plot issues, then you have the horrid WW design and inconsistent accent... I could go on.
What the hell happened here? Perhaps more confusingly, why are others praising it? To memory this is the 43rd DC animated movie I've watched in my run through, and this is the worst.