Ion just said so in the twitter space interview. Blizzard devs are not at the point where they could generate new dungeons that quickly. This mix of old and new is the current middle ground compared to the stale set of dungeons we have right now in SL.
Really? When has WoW in the last 3 xpacs released a mega dungeon at every major patch? We've seen a 1 mega dungeon every xpac but not every major patch. Major patch defined as the X.1, X.2, X.3 patches.
And more beholden to shareholders... How about this, why don't you pull an Elon Musk and buy out Blizzard and make it a 100% private company then you can make all the changes and priority shifts...