Exactly if they didn't intend to bring the whole package to the U, it just doesn't make sense.
The only people who are going to buy this are people who already played the first games on other consoles but deliberately chose to play the third one on the U, even if they know they can't port their data, just because they'd rather play on the new hardware.
This is my case. Played 1 and 2 on the 360 but I'll probably buy the third one on the U because I like the use of gamepad and I'd rather use my brand new console.
But we are going to be a rather small audience you have to admit.