As it has been mentioned that the map generator has been overhauled in the recent build, I was curious and gave flying a try, trying to reveal as much of the map as possible before MT crashes (wihich it does on my machine when worlds get too big).
Not too sure about the differences with before en detail but it seemed a lot nicer ad hoc. Had quite a large body of water in the map. The overall variety of cliff shapes seemed to have a bit more variety as well. Oh, and dungeons. Not on the screen but they're there. Very nice and leaves you wanting for more.
Going underground revealed caves linked together much more interestingly than before, I think. Linked parts seem to be far more stretched out. I tried to light one system up to show how far they go. Wasn't even able to light every branch due to a crash.