i can't speak to the difficulty of the job, as i had david fix my display when i sent the player in for service. however, i must say the 6-second video of him soldering the capacitor in place doesn't exactly look intimidating.
i had the dimmer problem at all temperatures, not just in cold weather. i also had the problem where changing dimmer settings via the menu resulted in somewhat random behavior -- sometimes brightness would go up, sometimes down, but eventually you'd get to where you wanted to be.
the capacitor fix has worked flawlessly. i definitely recommend the fix, it's nice to not have to fiddle with the settings all the time.
--dan.