The size difference is not superficial: the wagon's wheelbase is 80mm shorter than the sedan (or 65mm in overall length). Hence the very different stance.
Despite the extra metal, the wagon is just 20kg heavier than the sedan.
I'm not sure that any of that has a dramatic influence on the driving character of wagon versus sedan. Both are cars that please the enthusiast. I don't like the electric power steering at very low speed - it has a strangely inconsistent feel and loads up in weird ways during parking manoeuvres, for instance - but once you're up and running the Six has a crisp and engaging character.
Much of the appeal of our test car came down to Mazda's outstanding new 2.2-litre turbo diesel engine. With 129kW/420Nm, the performance is deeply impressive and combined economy of 5.4 litres might make you think twice about that desperate need to downsize.
Although the price might make you change your mind again. At $60,795 for our top-shelf Limited diesel wagon, the Mazda6 is certainly reaching up into premium territory. Having said that, the cabin is a model of elegant simplicity and the car is certainly well-equipped: the Limited comes with the full suite of what Mazda calls i-ActiveSense driver-assistance technologies, such as radar cruise control, smart brake support, lane departure warning, blind spot monitoring and adaptive headlights.
The Limited has sat-nav too: a touch-screen TomTom unit integrated into the dashboard. There are pushbutton controls arranged around the screen as well, plus a remote unit down on the console - but why are the buttons arranged in a different order on each? That's poor attention to detail in an otherwise excellent cabin layout.
While we're on it, why can't you set a destination on the TomTom (it locks out) while the car is moving? Seems like safety overkill. At the very least it might be handy if the front-seat passenger could have access - put a disclaimer on the menu perhaps.
The cargo area is only 13 litres larger than the sedan, although folding the seats liberates over 1500 litres of space. Nice detail touches include a tonneau cover that's actually attached to the tailgate.
I will end this story with a tale that's going to sound like it could easily be a contrivance of Mazda New Zealand's marketing department, but isn't. It's absolutely true. I had left the wagon at Auckland Airport overnight, and while I was away somebody in a previous-generation model - blue, just like mine - had parked next to me.
In fact, we both returned to our cars at the same time. He was naturally very interested in the new model, especially as it was the Mazda6 that had converted him to the world of wagons in the first place: "I had never owned a wagon before this one, never considered one. But I wanted the Six and I just thought the wagon was the best looking one by far." Presumably better looking even than the (now-defunct) hatchback.
This man would be keen to hear about the SkyActiv diesel engine, I reasoned, as that's a new feature for the Six. I enthused about it in a nerdy way; he was mildly, not overly, interested. But he did love the firm-order-only off-white leather trim in my car: "It's like an Audi or BMW". Well said.