I believe that this "low volume vehicle" could become medium to high volume with the SkyActiv D (I know of at least one guaranteed sale!). Current families with 1-2 kids should be content with considering the Golf TDI wagon and the Prius V - both great choices in my opinion. An aside, why would Mazda think buyers of the 6 would go for a diesel sooner than buyers of the Mazda5? A vehicle that weighs about 4100 lbs. (Mazda 5 with 2 adults, 2 kids, and luggage) NEEDS a diesel.
No matter what engine you put in it, a microvan will never gain the same kind of traction as a mid-size sedan in the US—the market for sedans is huge, and they'll have to sell quite a few, and at a premium to justify the costs of the diesel engine, so they are sticking it in the car that has the highest possible sales volume and profit potential. CX-5 is probably number 2 in line to get it because CUVs are also all the rage, and that model could use an engine upgrade option...
And I disagree that the 5
needs a diesel—it'd be nice, both in its torque and its fuel savings, but this engine is fine for this vehicle, unless you
need to drive aggressively...