It's not going to be so much of an issue for Nintedo. They are really playing by their own rules this time around. I doubt cross platforming is going to be a big part of the revolution strategy.
If the machine has run into space issues even before release then I dont see how things are going to get better. What it will most likely result in is games that last an afternoon like Gun , Kong and Kameo. If on the other hand developers have 27 GB to play around with, then there is no pressure to cut things short to save space (for other reasons , maybe but not space).