The balance is'nt great?
Since the 2000 season 27 of the 32 (a rough count) teams have made the playoffs at least once. I think that is as balanced as it gets. To say the NFL does'nt have "parity" and is not balanced is absurd.
The teams you pointed out have been undone in most instances by poor management (Cardinals, Saints). No, the Falcons have not had back to back winning seasons in team history but I'll remind you that they have done a hell of a lot more in the playoffs over the last decade then the Dolphins. (By the way, the Seahawks won playoff games in 1984 and 1983).
Spring training just began in MLB and there are 20 teams that know they have NO chance of winning the World Series. If the season began in the NFL right now, I'd bet 20 teams could say they have a legit shot at WINNING the Super Bowl. History poves this.
You don't want a salary cap? That's great. It would'nt have that big an effect for a few years but as time goes by the divide between the haves (Cowboys, Redskins) and the have nots (Colts, Bills) would slowly widen until the NFL began to look like Major League Baseball. It would not happen overnight but in 10 years the NFL would not even resemble what it does today.
I like the NFL the way it is...
Sure there are things I'd like changed. I'd like teams to be able to do more to keep their drafted players (a cap exemption for players that you drafted wouldbe perfect. It would reward teams that draft well and let them hold there team together longer if the player wanted to stay) and I'd like to see a rookie salary cap.
No salary cap would be a disaster in my opinion....eventually.