Do you think that a hard reset is necessary at all??
Yes, a hard reset makes it better. Over the weekend I went back to 8.1 because I needed the phone to be reliable.
Then decided to try 10166 again without hard resetting. It was very clunky and very slow, the start screen acted like like it was still running 8.1.
So, I did a backup, then hard reset, the restored backup. This seems to be working. The wallpaper on the home screen is shifted over, I was not seeing that before.
Also, I found a fix for a bug I found, using custom ringtones.
To use use custom ringtones, the mp3 file genre needs to be ringtone. After the hard reset this field is blank.
I connected my phone to my PC and recopied my ringtones that had the ringtone genre to the ringtone directory in phone memory.
Now custom ringtones work.