The main reason I didn't consider the 6 more strongly last summer when I bought a new car is that the reliability has not been great. Instead I bought a mechanically similar Ford Fusion which has better reliability for some unknown reason.
As someone who likes mazdas so much that I sold them for awhile, I can tell you that when the new 6 came out, the existing buyers ran away. The reason? The car had gotten too big and the styling, while not bad, lost some of the sportiness of the previous version. Mazda mainstreamed the car to better take on Toyota and Honda and as a result alienated their base. The other issue was a switch in financing arm from ford motor credit to chase which resulted in long time buyers not being able to get approved. Loosing the the wagon and especially the hatch also didn't help. Mazda needs to remember what makes them special and stop bring everything to everyone.