Well, that makes a lot more sense, but the only left that deters me is having to unplug/plug the hard drive every time I want to use it. My current HDD is single-USB powered and has no AC adapter. One would think doing that would wear the HDD out faster (cold starting/stopping the device while it's on), not to mention wearing out the cable and ports. Unless someone can prevent the Wii U from detecting it upon loading, it's going to be a PITA; knowing my luck, I'd probably end up formatting the drive. If there's not enough power for Wii U to get it detected in the Wii U mode, wouldn't the Wii mode be able to use it regardless?
get a Y cable, i have this one and it works great.
http://www.amazon.com/Cables-Go-28107-Mini-B-Y-Cable/dp/B0013LQD7Y