I got the Elder Scrolls Anthology recently and inside it were maps for each game, including a map for Skyrim and all of Tamriel (Arena, duh). But the shapes and border of Skyrim remains the same, even though the Great Collapse occurred between these two games. So I'm wondering, shouldn't the Great Collapse have changed the maps, and really, shouldn't a little chunk of Tamriel just be gone seeing as it's underwater now? Or is the Collapse just not represented on the maps for some reason...?

http://srmap.uesp.net/?centeron=College+of+Winterhold

I like to think that it did even though none of the maps seem to show it.

Northeastern skyrim certainly looks like it's been completely torn apart. It's even more apparent when you spend some time looking around down there.