Inline 6 is the relatively new hotness in engine design, very smooth and powerful, is now used by the European brands.
This should be great for the CX-9 and higher trim 6, especially if provided with RWD. This is inline with Mazda's aspirations to position themselves as a premium brand and inline with forsaking fuel economy for the US market.
I don't agree Hybrids are the way to go for Mazda, as a previous Prius owner, it is clearly a temporary solution until full EVs are more practical. Mazda should go directly to EV. Prius, which was the epitome of fuel-economy with practicality, has fallen out of favor soon after they stopped getting HOV lane stickers and new full EV coolness came to be, with all new stickers.
However, I also don't think that the premium push for Mazda will work. First, it must give-up the market below premium, as you can't successfully associate yourself with both. This would be a mistake. Also, premium level is a problematic status as it is not quite luxury. I think people buying luxury, i.e. willing to waste money on slightly better car, don't want to lose the status symbol of owning (mostly leasing ;-)) a luxury vehicle. They are all in, not part of the way in. They are not practical in getting a cheaper vehicle, which is pretty great but is missing the luxury emblem. They are literally pay more for the brand, even when it makes no practical sense.
Personally, while a inline 6 is sweet, I'd be hard pressed to justify buying it vs. a 4 cylinder Honda/Toyota. If it was only slightly more pricey than that and had RWD, I would be tempted to get one for my self. For my wife, there is no justification to get something like that.