Currently, players have the option to wait until being matched with someone who subscribes to cards. However, there is no option for new players who want to avoid being matched (for rated games) with someone who subscribes to cards, in order to avoid playing with many cards that they don’t know. I’d suggest an option in matching that lets a player prefer (or require) not being matched to an opponent who is subscribed to cards that they aren’t subscribed to.
An alternative or addition is to allow a player to prefer (or require) not to be matched only to an opponent who is subscribed to substantially more cards than they are, where that is defined as no more than one subscription tier higher. This would work well in conjunction with the “Copper” subscription option (to just Intrigue and Seaside) that I suggest here: http://forum.shuffleit.nl/index.php?topic=2185.msg8987#msg8987
. Then a new player who doesn’t subscribe to any cards could allow matches against another player who has Intrigue and Seaside, which is an easier starting point for beginners than the current Silver subscription of Intrigue, Seaside, Prosperity, Cornucopia, Hinterlands, and Guilds.