Judging by how many people in the Owner's Quiz thread said they'd seriously consider a Honda Fit if the 5 never existed, I can see the 2 taking some sales away from the 5.
What ruins the new design for me is the side waves. I don't like but could probably learn to live with the front and rear redesigns but those side waves are just plain f-ugly.
Ooops, Mazda 2, I thought we were talking about an MX-2. (rofl)

I feel like the Fit is closer to a Mazda 5 than a Mazda 2 or say a Yaris in that it has a pretty generous interior for a car its size and has some cool cargo loading features (like flipping the rear seats up to put a tall house plant in). I don't see the Mazda 2 and 5 compromising each others sales, the 2 is too small to compromise the 5's sales and the 5 is too big for someone who wants a 2 to consider.