MLB needs one.
Re: MLB - I would not be opposed to stiffer penalties for breaking the limits, but I hate the cap, which is absolute.
I think if you've got the money and are in a window where you have a few years to contend, that team ought to be able to tip the scales for a few years.
The Yankees don't just tip the scales, they knock them over and set them on fire. I think they exceeded the spending limit by over $100 million last year? The problem right now is the penalty is stiff enough to deter most teams, but not the Yankees. I think a better system would place a progressive penalty for violating the limit which gets steeper each successive year the team exceeds the limit.