I just found out that the stock Sony Home Screen has a hidden app launcher!!!
I don't know how to access it from home menu, maybe there is a secret key combination.
But you can launch it via adb for instance:
adb shell am start -a android.intend.action.MAIN -n com.sony.drbd.ebook.home/.activities.LauncherPageActivity
This seems to be a nice fallback if something like ADW Launcher is broken...
Note, that you cannot scroll it with page turn buttons!