Well it is a console redesign, its cheaper to make, so cheaper in quality so easier to break!
It's like the PSP to the PSP Slim...the original is a little heavier and of high quality, while the Slim feels lighter and cheaper and not in a good way. Sony might want to take some inspiration from Apple products(but then again those are super expensive so maybe not :/)
Anyway from what I've researched this problem is related to the HDD. Maybe Nintendo was smart in not including one with the Wii U?