I figured he'll never say any time soon. Because he either hadn't figured out himself who Oz was at the time, leaving himself some foreshadowing dimensions to play with later, or he had it more fleshed out than that but won't want to crap on what his colleagues chose to do by leaving door open for "Damn that would have been so much better" comments.

Either is quite possible, Johns starts a lot of things he never finishes, and I've never seen him take a dump on anyone else's work verbally.