I'm sure there is some commonality between the 330 and 350 but I would bet that it's not much.......They should get some A330-200's instead of the 350's. That way it stays in the same family. After all, aren't all Airbus aircraft wide bodies????
Are you at all familiar with the Airbus family??? If not, a 1 minute cursory glance of their website would have prevented you from pontificating rubbish.
The A330/340/350 are widebodies. The A31x,A32x are narrowbodies.
From the Airbus web site: "The A350 will have the same type rating as the A330.....Pilots with fly-by-wire experience will be able to qualify on the A350 after a short training course"
Management knows exactly what they are doing in this case. USAirways was the U.S. launch customer for the A321 and A330 and both have proven exceptionally well with the passengers. They have also minimized pilot training/recurrency and maintenance costs from what they were 5 years ago when there were numerous other types on the property.
If US were to go with a Boeing widebody, that would be a complete step in the OTHER direction in terms of fleet commonality. If the A350 doesn't meet the specs that are called for, then the airline can easily get A330's(-200 or -300 models) to fill the gap. I'm still wondering what's become of the A330-200 order from pre-merger, though.