To you'all with screen issues.
I double checked and the only settings for screen is under specific apps and not OS level beyond general output like 1080p and 16:9.
From what I've been reading, it has to be TV issues and settings. Looks like a few members on GAF have the same issue and its due to something in their settings that is stretching the already provided correct screen resolution. Double check to ensure your TV is set to 'native' etc.. .something that does not adjust the screen size at all.
Wish I had more for you. :(
EDIT: Solution for WiiU resolution issue: I realized I had the same issue. It's a tv setting, my tv has a "Wide" button that changes how it displays content. My tv was set to "full". I changed it to "full pixel" and the screen is perfect now.