Other than the whole Zoom Zoom effort, I feel like Mazda never really has pushed establishing a clear-cut and defined branding at least in the US. Word of mouth to date has kept sales sufficient for them here, but I really think that they need to step up their advertising and branding game.
I'm on my 5th Mazda since 2001 and it amazes me how many times over the years I've had a friend, acquaintance, coworker, or family member drive with me for the first time and say something like "Oh wow, I never realized how nice Mazdas are/drive/look!". I always felt like appreciating and owning Mazdas was a special club and only certain people in the know were part of that club, but I really don't want to see them go away or get diluted by forced partnerships with another car manufacturer with a potentially dissimilar way of approaching vehicles.
Mazda in my opinion has some general similarities to Subaru in terms of having a very specific personality, but Subaru has multiple promotional campaigns pushing safety, nostalgia (the parent/child driving ads) and humor/cuteness (the dogs). So, Mazda probably should up their game in terms of brand awareness and being a car company that people readily think about.
Of course, that's only good as far as the overall economy and trending of car purchasing might be--but upping one's portion of what might be an even smaller total pie size is still a logical move.