[quote=@Master Bruce]
<Snipped quote by Lord Wraith>

I think that moreso boils down to "Hey, look! A Batman thing you might recognize!", because that's been Warner Bros' logline from day one. If there is a Bat-character to milk money off of, milk they shall.
[/quote]

I also think this stems from WB's lack of confidence in DC products that aren't Batman.  Kinda like how early-years Marvel would slap Spider-Man's face in the corner of their covers, so even if you were reading some B-list book they'd be reassuring you going "hey, we're the guys who made Spider-Man, and you love Spider-Man, right?"  He's the one sure thing they've got; regardless of your feelings on incarnation (x) of character (y), everybody loves Batman.