I know this is a small thing but it actually really effects your productivity if you're used to relying on it a certain way.
When you're in the Advanced Editor mode creating a post in 2.2 and you highlight some text then click the "link" button to add a link everything works fine except for the fact that you have to actually click in the URL field to paste or type the target URL.
In the older version the "http://" in the field came up hightlighted automatically and you could just paste or start typing without having to mouse into the field and hightlight it again.
It still comes up with the "http://" hightlighted but you can't do anything in the field until you click in it and either start typing or re-highlight it to paste your target URL.
I know it's a small thing but just reporting the first thing I noticed since upgrading.