I own both ruins of undermountain 1 and 2. 98% of those maps are left to the dms imagination. I much prefer a paid professional to write the encounters.
41 FULLY WRITTEN numbered encounters. The originals of which I own were by far mostly left for the DM to populate. EVERY single level of this version is fully written, again a huge difference from the originals.
Here is a link to level 1 if you don't have roll 20.......http://www.belloflostsouls.net/2018/11/dd-dungeon-of-the-mad-mages-maps-are-intricate-and-massive.html
My best guess is that this book will have around 500 numbered encounter areas with the passageways mentioned by Chris Perkins that will allow for DM expansion
The main dungeon has almost 60 levels. There are over 1000 numbered encounter areas. I'm pretty sure that rapan is considered a mega dungeon. Now add in all the new 5e material which includes additional main dungeon levels AND brand new dungeons and I doubt it could be finished short of five...
Satine is now a official employee of Wotc. Obviously, working for the DnD team. This is an awesome addition which can only help DnD! She truly deserved this position because of the insane amount of good will she has done over the years.
I've been trying to find what is the rpg growth potential for 2020 but have not been able to find d anything. I'm curious to see what it could be. I think that by 2020, the rpg market will grow significantly.