NOTICE!! I believe we have a fix for this!! I have also updated my Extras+Info with no luck to fixing the screen sensitivity. However 5 days later I decided to look into this more because of how annoying it is. After playing with it for a few my sensitivity is now fixed!! Please follow the steps below it worked for my 1520 hopefully it will work on yours.
1. Force update to Extras+Info in the app store if you have not already.
2. After update reboot the 1520.
3. Go to System Settings > Touch, once in there toggle the Touch Sensitivity (either to Normal or High) and back out of touch settings.
4. Reboot phone one last time.
This should fix the sensitivity on the screen. I believe the update was the fix for the screen sensitivity, however the "extremely high" firmware sensitivity was stuck until you toggle it out of what ever touch sensitivity mode you were in. :smile: