The main stumbling block is that Ford vehicles in North American and those sold in Europe have successfully established their own recognizable and well-liked design themes. It's called "Kinetic design" in Europe where the best example can be found in the new Mondeo, and "Bold American" in the U.S. where it manifests itself in the form of the three-bar chrome grille.
We've heard from inside sources that there's also a clash of personalities involved here between Ford of Europe's chief designer, Martin Smith, and Peter Horbury who heads up design for Ford in the U.S. Establishing a single visual language for Fords sold on both sides of the pond hinges on these two working together, which we've heard is progressing albeit slowly. Mays tells AN, "I'm so pleased with the professional approach that Peter Horbury and Martin [Smith] have taken on driving us to the right answer," but we assume he has to say that, so take it with a grain of salt.
Now that Aston Martin is gone and Jaguar and Land Rover are on their way out, Mays has time once again to delve deeper into the designs of each brand over which he has dominion. Hopefully the hands on approach will keep Martin and Horbury motivated with the end result being some fantastic Ford designs in a half dozen years.
[Source: Automotive News, sub. req'd]