I hate that like everything else the world must revolve around Bruce Wayne in order to be sustainable. I hate that the decompressed timeline caused many of the more nuanced relationships to be erased.
I hate everything done to Diana and the other Amazons, it’s a complete lack of understanding of those characters, really.
I hate that Batman Beyond is set up in a world where Bruce fails, both as Batman and as patriarch to his family.
I hate the resolution of the Shyera - John - Mari.