On March 7, it was reported that Wii U consoles in Japan have been plagued with a variety of serious errors. Even though these problems aren't showing up in consoles that are in the US and UK, the error is still serious and needs to be worked on as soon as possible.
As of March 8, users in Japan can no longer access the eShop to download games or demos. If the user wants to download a firmware update in an attempt to fix the error, the error itself won't allow the console to update. With these issues currently affecting Wii U consoles in Japan, it's possible that all other consoles in other countries could eventually have the same errors.
To fix a terrible error like this, Nintendo needs to get to work now and fast. They have said that they are releasing a patch this weekend to fix infected consoles, but it can't be downloaded as a firmware update. However Nintendo decides to roll this patch out to consumers, they need to do it right.
It's normal for new systems to have errors when they first launch. It's important to realize that the Wii U is less than 4 months old and bugs will be expected. For Wii U consoles all around the world, owners have complained of the slow loading times. In January, Nintendo announced that they will be releasing a patch in Spring and another in the Summer to fix the slow OS. Once Nintendo has everything fixed, they'll be ready to release more games which the system desperately needs.