Possibly. But it is a good grain of salt to take if the makers are advising against it.
Other thing is to just optimize for your needs. I am using a 500gig HDD in my Wii U and been using a 320gig one for long time, before even the brazilian outbreak of samba loy in our Wii U's. Only crappy thing is Wii U's low power output over USB so you need Y cables for small drives or drives with external power. Aside that hard drive is your oyster of data when it comes down to having data with Wii U. Also after 128gigs especially in europe the price vs. size is much better with HDD's. Especially if you have some old HDD's around and all you need is a USB enclosure for your drive, which is what I have done personally.
