You could just wait for it to be officially announced and some driving reviews before making a final decision (scratch)
I just think it would need to be an epic engine to make it worthwhile in the US market. Consider that:
1. MPG is no better
2. Diesel fuel usually costs more than low grade gas (at least where Ive lived)
3. Few CX-5 buyers tow
4. Mazda is a sporty brand and diesel doesnt have a sporty reputation (even if modern engines are better)
5. Diesel still has a bad reputation from the German car scandals (whether warranted or not)
6. Diesel engines usually dont sound great
So what in the world is the Mazda salesperson going to say to convince me to even test drive the thing?? If Mazda doesnt have a headline answer to that question, they shouldnt bother in the US. I just cant imagine much demand.