With Carter, I've had the sense that he might be a guy who needs a really specific locker room to thrive. Remember, 8 other teams passed on him. It could well be that the Eagles turn him into a HOF-caliber guy and there's non-stop whining about passing on Carter for the next two decades, but if Carter needs a team that has veteran leadership and an experienced coaching staff to get him motivated and keep him motivated, then I don't think it would have worked out for the Bears.
Maybe it's sour grapes, but I can understand the justifications for passing on him due to character/motivation issues.