We have experimented with allowing you to travel on both.
At a minimum, you can decide where to go on the 2D map.
If we have the time to make it more involved, we will. There's a strong contingent of 2D map folks on the team as well.
I also think the map section of the game will be...
Think of the 2D as a kind of automap for the region. The region is represented in 3D for top-down navigation and exploration purposes.
Very similar to Gold Box for example -- just a different exploration perspective (in some cases).
The real added complexity is the fact that you can enter...