This is going off topic, but i think to put it simply, the Panthers and Patriots have been extremely consistent - which is an extremely important attribute. The Cardinals' offensive and defensive rankings (and our eyes) show that their average level of play is extremely high. But they've had stretches of poor play that has cost them games.
I think when the Cardinals are at their best (and if they remain healthy), they're better than the Panthers (and maybe even the Patriots without Edelman). But they need to learn to play consistently well for 60 minutes.
So if we rank teams on how well they're capable of playing, you could make an argument that the Cardinals are #1, and they're almost certainly #2. But if you rank teams on what they really have shown that they are, which includes their consistency or lack thereof, you have to put the Patriots, Panthers, and probably Bengals ahead of them.
...dave