Sorry to hear. I can't figure out who is ultimately to blame for this design - Ford and Mazda collaborated on engine design for many years. I guess it isn't surprising that Mazda enthusiasts on this forum pin all the blame on Ford. However, Mazda went ahead and installed it in their vehicles so they must bear some responsibility, no?
I have no idea how the class action suit will play out. Hopefully the discovery process will bring to light what the failure rate is on these things. Ford/Mazda put this engine in millions of vehicles. It's easy to find instances of this failure on the internet but considering how many vehicles have this engine I can't figure out how concerned anyone should be about their particular car.
As far as not knowing about the pedigree of the engine - did you never look under the hood? It says Ford in several places...