I do agree if he remains an unlockable AT there'd really be no reason to show him prior to release, it's not like he has any games to promote, so pretty much any way you want to look at it... chances are it'll be a wait.I certainly thought of posting about that possibility, but I decided to keep relatively optimistic.
He was an unlockable AT, so that might hurt the chances of him getting shown soon if he is a returning AT and not character, so either way we probably won't know for a long time.
The only exceptions I see are if he's moved to "starter" AT and Sakurai just feels like revealing him for some reason or if he actually becomes playable and Sakurai once again just feels like revealing him for some reason. There's really no event his reveal would tie into... but then again if he's a starter (which... eh... I wouldn't count on) it's not like there's a necessity to have a tie-in reveal, any reveal will get people pretty hyped.
I just hope this isn't another case of not getting ANY GS content revealed until post-release, though it very well could be. Hopefully we'll at least get more than an AT and single track this time, even if we don't end up securing a playable position.