Ze RedTech is here! I probably shouldn't post in the dead of night, but I want to get this off my mind before I go to bed...
The other day, I tried to go back to the Wii U menu from Wii mode. I pressed start, then immediately heard something weird and got a message saying the system files were corrupted. Apparently, right after it gave me that message the system froze, as I was unable to turn it off or press any buttons. So then I unplugged it, plugged it back in, turned it back on and it worked just fine, nothing was deleted or corrupted. However, the way my Wii U is set up makes it a huge hassle to unplug it, so I did not test it again for confirmation. It's weird how my system has all these weird problems. 
UPDATE: The NSMBU connection problem and GamePad Display freezing problem have been resolved due to the new update. However, the Miiverse auto-completion freeze is still there, and unless Nintendo makes a major change to the keyboard function I doubt it will ever go away... BTW I don't ever use that function anymore, so that's not a big deal. I don't think I will send my system to Nintendo because I heard it takes weeks to get it back... and these aren't major anyway. However, I wanted to know what others thought. I don't want to format either, because I have 1 and a half years of game data...