Last year United made some changes to its elite qualification late in the year. They did it considering the problems that their customers had. I don't think that they should be disallowed from doing so. This year NW is having a promotion which allows members to get status miles with non-flight partners. The rationale stated is that business flying is taking a downturn, and they want to help their customers maintain their status. If you disallow any changes, then the airlines will not be able to fine tune their programs.
The flip side to the x+2 argument is that it legitimizes any changes to FFPs. I am not ready for increases in the award tables in 2003. Ultimately I think that it is consumer reaction, rather than govt regulations, which will force the airlines to act a certain way.