Some skepticism from me as well. There will have to be a massive overhaul of pretty much every system to make DMing in real time feasible. Textures will need to be selectable to be part of prefabs, monster and item code will need brand new UIs, as will dialog and scripting. Well, scripting will probably have to just be some simple prefab things like traps and journals. Presumably someone won't be able to make a whole dungeon full of interesting stuff in real time as someone plays, and they'll want to set the map up before they invite players, just like a (good) PnP DM will spend a lot of time setting things up before the players see anything.
If its planned for post-release, that would probably ease the pressure up a bit. Though at the same time if they could get the DM systems in place early, it could potentially expedite development of the rest of the game (if it's powerful enough to do that).
