FWIW-McNabb isn't a BAD QB, per se-but he's just not your typical WCO offense. His biggest flaw is that he has problems holding onto the ball too long, and he locks into receivers too long as well.(the tv announcers have pointed this out many times)
When Garcia was taking snaps under center, it wasn't so much that Reid decided to run the ball and have a more balanced offense, but it was OBVIOUS Jeff just had a much broader knowledge of this system than McNabb did.
Ditto Feeley-sure, he sucks, but he AT LEAST is able to get the ball out quickly(and throw fairly well into those tight seems)-like we saw him do in the NE game last year.
Ultimately-it's no surprise that those so-called WR "busts"(whether it's Reggie Brown, Kevin Curtis, Hank Baskett, LJ Smith, etc) just look like ALL-PRO's when [insert Philly backup QB] is under center instead.