It needs to be deep enough for TCG enthusiasts, without being offputting to newcomers
Boromir, Warden of the Tower Chief: For three mana, youll be able to get a 3/3 with vigilance that counters enemy spells that are cast without spending any mana
With the Shift keyword, rather than costing five ink to play Kida, Protector of Atlantis can be played for just three ink if placed on top of another character named Kida - thereby making it a lot easier to get this card out
At the beginning of each players draw step, that player draws an additional card, then discards a card
To make things more confusing, some cards in certain Commander sets could only be found in the (non-draftable) boosters for the main set, and not in the accompanying precons