That's essentially an impossible standard though. I think you're setting the bar too high if that bar is more potential on your own system than multiplatform elsewhere. That's a bar no one will ever meet at this point worldwide, Microsoft and Sony included. What Nintendo needs to do is prove Wii U to be a sizable enough marketplace to be included, not be the overwhelmingly largest marketplace.
Also, Namco Bandai's sort of a bad example for Japan focused 3rd parties given their announced products so far. Games like Tekken and a casual arcade game are easily identified as targeted worldwide products, with far more western that national potential. If they'd announced stuff like Gundam and Taiko upfront you'd have a point, but Namco Bandai in effect is an example that runs counter to what you're saying.