Stats. Always a reliable metric.
I'd rather start gauging their potential when we see them play complete games. Almost coming back when the other teams take their foot off the pedal isn't enough.
And as for the teams we've lost to? Carolina damn near beat ATL if not for bad luck. They were much closer than we were. NE has lost to the Ravens and the Cards... neither of which I'd call great teams. These teams aren't on such an echelon that the Broncos shouldn't have been able to compete as long the Broncos had any skill whatsoever and played a decent game.
I've seen little since the Pitt game that instilled confidence in me. Garbage time almost-wins just don't provide any comfort.