\ but the 15 was so much nicer on the inside, looked better on the outside and felt much better on the road.
Since I'm going against the grain a little here
There's no going against the grain---we need people to buy this new mustang so Ford see the value in continuing to improve it.
Not to mention, objectively, one expects the new version of something to be better than the last. There's some controversy, I think, about whether that's true for the new mustang from a performance perspective. At the end of the day though, unless the car is living on a race track, the only that matters is that you feel that you are getting a better car.