Yeah Mark is never backward in publicising his stuff, he'll do it here without fail (even if the scoop is with the Hollywood Reporter or something it'll be linked in the forum same day and almost certainly trailed in advance), but the time has to be right.
There's a 'damned if you do and damned if you don't' element at play because if he announces some stuff in early development that may not turn out as planned then the internet is first to cry foul and get upset 'promises' were broken. We as mods sometimes get more info in confidence and see plans change because an artist may sign some exclusive or fall sick or whatever.
So it's great that Josh has so much enthusiasm for the next material, fans like him are the best, but patience is a virtue. Keep tuned to Millarworld and Mr Millar's postings and you'll hear about any new projects as quickly as is feasible.