I'm on the opposite end of the spectrum. I prefer a soft cap system, but with a geometric luxury tax penalty rather than a linear dollar-for-dollar system that the NBA and other sports utilize.
Spending $40 million more on players and then $40 in tax doesn't add up to a whole heck of a lot when your team is making deep playoff runs every season thanks in no small part to high quality depth. The revenue generated by a single playoff win would possibly offset a $40 Million luxury tax penalty.
I'm surely for a rookie salary cap as well, and/or a rookie salary cap credit system. If you have a franchise rookie player, he ends up being a bust, and you have to cut him, rather than accelerate the contract you as a team would get to wipe that contract off the books for sake of only the salary cap. The guy would still get his green, but your salary cap would be clear to go out and redraft someone to take his place. This would only apply to players drafted by their original team.
I do not think a franchise should be held hostage like San Diego was with the Ryan Leaf deal. It killed the Chargers for years.