Speaking to Eurogamer at GDC last week, Rein said Wii U – which was unveiled at E3 last year and will be shown off at this year's conference ahead of a release later in 2012 – was much changed from what was unveiled last year.
"I like the Wii U," he said. "I think E3 will be a big eye-opener for people. I played Batman: Arkham City on Wii U and they're doing some really cool stuff with the controller.
"Do you remember the Zelda demo they had on it? Would you not buy a Wii U just to play that? Of course you would. That's what Nintendo is all about. Their hardware is the software delivery service for their great content.
"That Zelda demo was gorgeous, and we can do even more than that with Unreal Engine 3. I think it will do great."
In terms of actual content, the Wii U announcement was thin on the ground, with Nintendo showing tech demos rather than full-fledged games. One in particular caught Rein's eye, and he enthused at the prospect of developers crafting similar experiences using Unreal Engine 3.
"Did you play that Battle Mii game? Two players with a Wii Remote and Nunchuk and one would play with the Wii U controller? I would buy a Wii U to play that game in a heartbeat," he said. "And I hope people make those kind of games with our technology.
"I think we've yet to really see what the Wii U can do and I think at E3 this year they're going to shock us."
Perhaps the greatest barrier to Wii U's potential for success is the difficulty Nintendo faces in wooing the expanded audience it did so much to create with Wii, which has since been cannibalised by browser, social and mobile games. Rein, though, believes that the strength of the Wii brand will do much to sway those that analysts insist will not be interested.
"It's a great brand that a lot of parents really trust," he said, "and they're probably ready to buy their kids an HD Wii that does much more than just being an HD Wii.
"I'd love it if they'd [released] it last year, but I'm excited for them to do it this year. I'd be shocked if it doesn't do well."