I just don't read it quite that way. Batman was always dark, at least he's been retconned dark, so I don't really buy the interpretation that Zee's mindwipe suddenly turned him dark. His whole MO is the dark and mysterious thing, straight from the origin, right? His whole mindset comes from trauma and darkness, Always has, always should.
It would be funnier if the mindwipe turned him into the goofy, 50's 'old chum' Batman!
