Add me to the count. I have a 920 with "Dead Tiles". I have unpinned, repinned, uninstalled, reinstalled, uninstalled apps that show up in the advanced section of background tasks. Went into every app on the phone and disabled lockscreens, background tasks, live tiles (except for the 7 I wanted to keep), rebooted normally, rebooted with power and volume down, cleared IE history and cache, cleared temp storage... And for a day or so a few tiles actually worked, then they stopped again. I did all of that stuff again, and the majority of them still aren't working.
It is so annoying to have a feature like this not work for so long... I really do not want to do a hard reset.