If your wife decides to buy a Lexus, here is an interesting comparison review of the 2 cars for some light reading. If the main criteria for you in choosing a vehicle is a high crash rating of the passenger front, then it shouldn't be too hard to find an alternative. I respect your own criteria but I doubt many buyers are going to go to the NHTSA website to do their own research on specific compartment crash rating before choosing the vehicle to buy. This has nothing to do with the popularity of Mazda in your country which this thread was all about. Many many factors are considered in choosing a vehicle, everyone is different I guess.
I have to say, I'm pleasantly surprised with how much you folks seem to love Mazda, and specifically the CX-5. It's absolutely a darling in Australia.