Freezing or hard lock is rare but it seems like everyone has gotten it. Apparently there is a patch releasing as I type this (another VGCer is downloading it now) and hopefully it addresses this.
I got my WiiU at midnight on nov 18th. I play it A LOT between everyone in my house. Its froze up on us 5 times. It was truly a rare thing overall, but obviously a bug introduced at launch (as reviewers said it never happened until the launch day update).