After a certain Wii U update, Virtual Console games and a few other things were set to be displayed using only a 4:3 portion of the screen, so even if you change settings on your TV, certain homebrew channels will not load in 16:9 like they used to. There IS a way around it: use USB Loader GX, install the channel forwarder onto the Wii menu so the aspect ratio stays at 16:9, and launch everything from there (or use an ISO + Ocarina or something). I'm not sure if the Project M loader can be loaded through GX since I've never used it, but those are your options if you want to play Project M in widescreen. That's how I do it, anyway. Note that this will require you to install custom/hacked cIOSes, which can be tricky if you don't know what you're doing, but there are plenty of guides available.
