Planning on taking a Wii U GamePad to a friend's in another region? You can, but it just won't fully work for now.
According to reports, including Japanese website Rocket News 24, unlike other controllers the GamePad is specifically locked to one region. For example, a European GamePad will not be fully usable in North America, and vice-versa. A translation from Destructoid notes how firmware updates (and presumably downloads) can't be run using a foreign GamePad, but whether or not it can be used to play games has yet to be confirmed.
It's likely that the only reason Nintendo have region locked the GamePad controllers (compared to previous peripherals) is the potential issues that could arise with different software versions running on the device.
Whilst a GamePad does come as standard with each system, so it shouldn't be a major issue, when multiple controllers can be used in the future, importing could have become an option.
Deal breaker or not a big issue? What do you think of Wii U GamePad region locking?