The scale of that map is dubious, just look at the size of the airports. This map appears to be much more accurate:
Gameplay footage is starting to leak out, but Rockstar is quashing it pretty quick. Some observations from what I've seen:
1) If you clip your plane's wing off a building, your wing will fall off and you'll spiral out of control. Awesome.
2) The Busted and Wasted screens are back when you're arrested or killed.
3) The strippers now take their tops off in the strip clubs. Truly, we have entered video games' golden age.