When I heard they were first revising the JLA to include basically the "Magnificent Seven" I thought, "Ahhh. Finally. Some JLA stories that involve my favorite Martian."
Wait, what? He's not on the team? They put all Silver Age heroes on the team, but decided that the seventh slot should go to....Cyborg? He wasn't even around in the Silver Age. He has no history whatsoever with this team. He's a Titan.
Ahhh, okay. I guess they're saving J'onn for the new Justice League International title.
What? He's not on that, either?!
Then where is he?
He's on some Wildstorm title, with characters I never knew existed. My only (heavily-biased, bitter) guess is that the conversation went something like this:
Comic Editor #1: Okay, so we've got to integrate Wildstorm into the DCU somehow. We need some C-list DC hero to bridge the gap. Hey, Dan? Who's a pathetic, loser character that no one cares about with copius amounts of untapped story potential that we keep throwing under the bus?
Dan: Martian Manhunter.
Comic Editor #1: Thanks, buddy! You're the greatest!
Then they all go out for coffee and burn down an orphanage on Christmas Eve.