Based on what comes out of the Grassroots Grind SBC I would expect they will be releasing 81+ double upgrade or something similar that requires rare golds and commons. They will expect us to farm the packs and completely stack up on commons and rares, to then sit there for half an hour making god knows how many 81+ double packs for most of us to see very little return from it. For some reason they like to treat it as a statistic for keeping us on the game, rather than making sure it is actually fun.