It seems to me completely closed-minded to dismiss a rule change simply because the draft has already taken place. Who cares about the drafting strategies other than projected impact on the field. If a player you drafted isn't productive relative to NFL rules then they won't be playing long anyway... (i.e Roy Williams).
The concept of fantasy is to enable the masses to participate in the great NFL... Ideally, when managing your team, you are charged with the task of projecting impact on the field, not delusional fluctuations of value. That's not to say that there aren't many plausible, if not valid, varieties of fantasy... because there are many interpretations of production. But, if everyone agrees that a rule change would better reflect the TRUE impact on the field (which they had in this case), then the rule should be changed as soon as possible! Roy Williams was drafted very late in my league; it is evident that future impact on the field is taken into account because he scored very high last year.
I just can't see anyone protesting that they should have won a game because they had more tackles and less pass defensed than their opponent... It sounds silly because it is!
On the other hand, an unjust loss due to having more pass defensed and less tackles... just ain't right.
Nobody is going to lose a championship unJustly with a justified rule change but, one might lose a championship unjustly with unjustified rules.