I have always had abnormal tire wear on the inside edge of my front tires. I've seen this on other Fords as well. When sighting down the tires from the front, they have always looked like the bottom of the tire was further out to the side than the top. It was aligned by the dealer and by various other front end people over the years and it always looked the same and they said it was within specs.
This time when I got new tires I talked about this problem. They installed new, more accentric "parts" (?? atop the upper ball joints) which allows more adjustment than the factory one. The front tires now sit perfectly straight up and down. Handling, cornering, etc feel fine and maybe even a little better. I'll be checking the tire wear carefully to see if this cures the problem.