Hello,
this is a quick list I've made after half a day of TM2 usage, hope it can be helpful:

1. Wrap Column with Soft Wrap deactivated doesn't show any wrap marker (on TM1.5 we got a vertical line and a ligher or darker background color on the right side of it, which was a very nice 'hint').
2. I don't know how to reproduce it, but sometimes when you open a folder dragging it over the icon, the file browser opens all the folders in it (and it takes a lot of time!)
3. Double clicking a file in the file browser to open a file? Why not a single click as before?
4. Chosen font is not preserved.
5. The bookmark flag icon replacing the simple star icon is plain horrible :) Moreover, if you have an old bookmark from TM1, you can still see the star icon.
6. The new search is very, very nice. Non the less, a button to batch check/uncheck results would be appreciated when you have to do mass replace.
7. Personally, I found the last two icons on the top bar of the file browser kind of useless (the Home and the Computer), while the smart folder with SCM status is pretty cool, but why not adding SCM badge
directly in the main file browser view (a-la XCode)?
8. Selecting some chars and then Folding Current Block causes the selected text to be replaced by a three points char and is not possible to "unfold" it, even if you close and reopen the file.
9. As far as I can tell, there's no way to add a new file to an existing folder within the file browser (You can double click an empty space in the tab bar, but it's not obvious and if you have a lot of
open tabs, there might be no empty space). Even the New Folder command is rather hidden. The old icons to add a new file and a new folder from the project drawer were much better.
10. If you have a single file opened, you can't close it without closing the whole application.
11. Projects are gone, still you have a Go->Project Folder command

I will update the list as I find other issues, meanwhile thank you very much for this alpha :)