Greg was originally brought onboard during TBC, he oversaw the development of Wrath of the Litch King.
Nice guy, some cool ideas but I don’t think he’s quite the guy for the job regarding Classic WoW. Who knows; maybe he would be good at it, but you’re only looking at the lead developer roll that’s controlled in part by upper management now days (Activision).
As a result their power and authority dictate the direction the lead developer takes and as such that flows downhill to the developers under him to implement the “goals” of Activision.
As a result of this even if they did bring back Greg it would do very little to fix anything because the Lead Dev has his hands tied in a lot of ways that you may not understand.
Essentially he’s a well paid whipping boy now days.