I got part of the answer from this stream:
https://www.twitch.tv/videos/763351879 about 14 minutes in. 3 acts like DOS2 but, as you said, how long those maps/acts are is the question. I never completed DOS2 so act 2 in that game being very long is probably good news for BG3. I'm definitely hoping the later maps are expansive.
I don't know if it is really indication of anything, but if you go to the edge of the EA map, you can see a map of the game and there are like four or five places you can potentially go.
In Baldur's Gate 1&2 some locations weren't shown on the map until you progressed through the story. Seeing how clustered the locations appear at the moment & how big the background map is, I'm hoping that's the case for Baldur's Gate 3 as well. Also... hopefully, each of those locations is as big as the EA area. I managed to clock 140+ hours on this one map and I'm sure there are still a lot of things that I missed & things that aren't currently available (that will appear further along the development process) so having five or more maps like this one would be a dream come true.
