I find the new one much more bothersome than the classical one. I keep getting lost with the separate windows and need to find the one I need to bring up.
Having separate windows and providing for them to be moved about the screen allows for more display of the map or, if windows are desired, an option to place them over an inactive region the map..
Once you get used to the dialog display options at the bottom of the screen, the windows can be turned on and off at the user's discretion.
Also, if you end a game with a window display you're comfortable using, the next game you open will restore that configuration at start.