Not sure it would discourage competition. One part of that is no one quite knows the rules! The other part is that there is a fairly large chunk of MVP's - at least in SQL - that rarely change, so having it known that there's at least a chance I think might actually boost interest.

Would those six year plus MVP's stop participating in the community if they were out for a year? That could be good, let them recharge, or bad I guess if they only do it to retain their MVP status?

What about showing what the contributions that led to the award? Doesn't that benefit the MVP by showing the community Steve Jones wrote x editorials or answered so many questions, and where? Or that he organized a user group?