The 6 has a advantage. This platform was designed to be the new X-type and the Volvo S60. (next gen versions) And so, instead of making a mediocre family car and a POS luxoboat, it's more of a fairly good luxocar and a great family car.
Seems interesting, but I don't trust Mazda after our last 626. As well, I much prefer the RX-8.
Mazda already makes a 5-door hatch and a wagon, for everywhere else, they said the wagon was here next year and the 5-door may be a possibility (They think they will get the Saab 9000 Effect - Existence of costly hatchback model will snuff out sales of both itself and sedan models)