I don't want to pimp the podcast I am a part of more than I already do, but if you want to hear an elongated response, PM me, and I can direct you to where we discuss this at some amount of length.
That said, the short answer would be that the "super hero" aspects of DC all fit basically the same level and scope, and I like the idea of these god-level beings intermingling and having they mythologies affect one another. You have meta humans based on Earth, Mars, an various aspects of the universe, and it all feels huge and interconnected. I don't mind the idea that the Speed Force and the Guardians of the Universe and Apokolips all existing and interacting on the same plane. The universe is a huge place, and all these beings fighting for different pieces of the pie creates a fun pantheon.
But when you bring in a lot of street level characters, and the Bat-family in particular, those low-to-the-ground characters feel essentially pointless. And to counter that inadequacy, the writers and editors have to pump their tires to ludicrously unrealistic proportions (which is when you get a Batman who is capable of taking down the JLA with silly plans). Those stories are fun and goofy, to be sure, but really destroy who and what Batman (and his universe) is supposed to be.