I don't really see the point of hamstringing us from the get go. If people want to continue playing even after a certain number of seasons, they should have the ability to do so. I suppose the only positive is that it would allow you to plan for the appropriate number of years as a GM, but if you know how many seasons you're going to play you should be able to do that without the need for an expiration date on the league. Anyway, the balancing act between preparing for the future and mortgaging everything to play for now is half the fun in GMing.
I've said it a couple of times before, but I'm strongly considering just sticking with the Packers for next season.