Uh, no rules for THIS year would have been changed. This was for NEXT year.
IMO, changing the number of players someone can keep for the year directly following this year constitutes as a rule change for THIS year, not next. Why? Because there is a chance that at least one person in the league (it may not be you) took into consideration the number of players they can keep for next year when they determined their drafting strategy at the beginning of this year, and drafted based on that. Changing the number of keepers would be unfair to that person. Even if you allow people to make trades so that they can make moves to accomodate this rule change, that person would be trading from a disadvantaged position.Here is an extreme example: Person A knows that the league is a 3 man keeper. He already has three top tier young studs (eg. Tomlinson, Moss, Culpepper). Looking over the players available in the 2004 draft, he doesn't think anyone will be good enough to keep over these three guys. So he decides to go with a strategy of drafting older veterans and ignoring young players, because even if the older players bomb, he still has arguably the best keeper trio for next year. So he goes and fills his team with guys like Jerry Rice and Charlie Garner. Then, the league decides mid-season that for 2005, you can keep 4 players. Suddenly, Person A has one more keeper spot to fill and, unlike the majority of other owners who voted for the rule change, does not have a viable player to fill it. Sure, he screwed himself by bad drafting. But if he knew ahead of time that he could keep 4 players, he would have definately not drafted all veterans.Thus, IMO, if there is a rule change concerning keepers, it should never be made based on THIS year's rosters unless you are making the change before THIS year's draft, which in your case has already passed.