So shadowcursed lands are act two? Interesting, becasue in EA it seemed as though we were meant to be choosing between it and the underdark as the routes to moonrise tower. I wonder if that was the case when EA first came out but along the way they made the shadowlands in their entirety act two? It doesn't make a difference to anything but it's intereting to think about. Also interesting from a story structure level. Act 2 in a story is typically the longest act and the part where most of the action takes place, with act three beingwhere everything wraps up. But based on what we've heard, being in the city is going to be the biggest part of the game. So I wonder how that will play out in terms of experiencing the story and how the pacing feels.
The impression I got was that Moonrise Towers is going to be a hub and various quests will originate from there. Whether you get there late A1 or early A2 could depend on how much of A1 you do or various choices taken in A1 resulting in more or less A1 content to get through. Also see my comment above about some one spotting a level five character in Baldur's Gate.