In many games that have established elo-point systems (such as soccer, chess, etc.) they have established solid rules on the determination of points. The only variable with which points are awarded are usually based on skillful, lawful play. If the rules of the game themselves were unstable and changing frequently and drastically, it wouldn't be an accurate estimate of how well a person plays, but rather how Lucky
he gets in any given game based on what wild card rule happens to be in effect at that moment.
Understandably, this game is centralized on luck and chance, but to have a game format called "Elo" would mean establishing rules that are as concrete as possible thereby honing in on as very few variables as possible with which to measure skill during competitive play.
If there are any adjustments to the elo
system, it should be limited to the manipulation of banned cards, and nothing so drastic as shifting from t1 to t2 to some weird off the wall card format every week, or every two days, or whatever you guys are having in mind.