If the game was annoying or slow to play (against the AI), upgrades would be just too much hassle. Yes, it can take a while to upgrade a whole deck, but then again, who says that you have to use upgraded cards in PvP? I actually enjoy the unupped PvP format because it doesn't exclude new players from competing. I have talked about this a few times, but I believe that incentives for PvP would be a great way to encourage players to venture out of the AI grinding. If the League gets going, there could be some kind of reward for tournaments or PvP points that could serve as an alternative to False God grinding.