The Heathrow flight does not leave during the European push, which means USAirways has gate space for this flight. I doubt the 767's will go anywhere for a while. THey still got quite a few years left on them, and I doubt they would be refurbishing the planes just for them too get retired...
Kirby stated that US Airays still plans too add about 3-4 international destinations a year, and stated that since a lack of gate space is provided at Philadelphia, they {US Airways} would have to look at other hubs {Charlotte} to do international flying. This could mean switching low O&D flights from Phili that rely on connecting traffic, and switch it too Charlotte while adding Asian flights out of Philadelphia.
Pheonix could see London, and if lucky, Frankfurt.