The affordability equation on this is off significantly for anyone that started after the SPS air drop. This change could be done after Rebellion launched and then a modern league would exist that's somewhat affordable to be competitive in.
Alternatively it could be phased in and applied to Bronze and Silver to start and then assess the impact. There aren't enough players at Diamond and Champion right now to get a consistent on level game and making that more difficult is only going to hurt the underlying game.