I'd be amused if they called it Control U :P

I've been calling it the tablet controller even though it's not really a tablet. Screen controller works too. I'm curious what Nintendo will end up calling it.

We here at the NWR forums are being pro-active on that matter

Naming the WiiU controller (a poll to pick it's name)
http://www.nintendoworldreport.com/forums/index.php?topic=34754.0

I remember when the controller that originally came with the console was just called the controller.  Only aftermarket controllers (like my beloved NES Max) had special names.  The only exceptions I can think of off the top of my head are the DualShock2, SixAxis, and Wii Remote, anyway.

The controller that shall not be named.

I've been calling it the Wiiblet (Wii + Tablet)

U Book