Looks like its heavily beefed up the graphics. I'm thinking Nintendo realizes all the whiners about 'next-gen' graphics and is focusing on making it look like you're actually small and walking in / under grass and stuff. That latest video linked above is already amazing looking. If they also beef up the character models and add even more tech.. man on man there will be no argument at WiiU's capabilities.
Personally, beyond fanboy arguments, I don't care and just want a great game like the other Pikmins. Though I thought the game was basically complete so I really can't think of any other reason for a delay from Q1 to Q2. Unless its a request to not be directly competing with a 3rd party and the summer months will likely have nothing else of importance.







