If you hit home in an app it would take you back to the launcher home screen instead of the screen you were previously on. Seems a very small thing to me but it apparently drove some people crazy.
Another problem is that in many third party launchers, there is a specific function that can happen if you hit home while already on the default home screen. Most good launchers will have a way to turn this off, but often the functionality is useful - say, it can show all of your home screens in smaller images at the same time, so you can choose one without having to slide to one that is many screens away. The Aviate launcher toggles a particular function on and off when you press home, so, on the Droids, it now quickly toggles back and forth, making pressing home useless.
It doesn't drive me crazy, but I do find it mildly annoying that I can't go back to my default home when I'm in Nova launcher. I'm actually more annoyed that it's taken five-plus months (and counting) to get it fixed.
