I appreciate You trying to improve your product, but I honestly think the new interface for staging and viewing current uncommitted changes is no good.
The old way of dragging and dropping files between the staging area and the changes on the working tree worked great. It worked especially great for staging a selection of files at the same time (command-clicking multiple files, dragging them into the staging area) which is a bit more involved now (command-click multiple files, right-click, select "Add to index").
The new view also takes up significantly more space than the old one (I'd estimate each file takes about 1.5 times the height it did in the old version => it fits 33% less files).
I also don't like how the staged changes scroll away when i scroll down into unstaged ones.
On the right side in the diff view, staging single lines now requres a right-click. I do, however, like the new, cleaner look more than the old one.
tl;dr: I really don't like the new way to manage uncommitted changes/staging changes, please make it more like the old one 
For me this means I'll stick with 1.8.1 for now.
