I think maybe people have the wrong idea about a "three-door hatch". We know the Focus and Golf have 3-door hatches that are proportionally the same as the 5-door versions. I can't see them doing that to the MZ3 - it looks like it was meant to have four doors, no more, no less.
What if they're referring to a 3-door sport hatch along the lines of the Celica, Eclipse, and RSX? They certainly have significant US sales, particularly in the coveted "youth market". Why doesn't Mazda try for a piece of that? The RX-8 is too expensive, even in auto trim. The rumored RX-7 won't be cheap either. Mazda really should have a coupe in the low $20,000 range if it wants to attract sporty car buyers, based off the MZ3 platform.
New MX-3 anyone?