I don't have so much a problem with cards as I do with ambiguous rules:
The amount of each type of card in existance is determined as follows, where P is the number of players:
Common: 3*P
Uncommon: 2*P
Rare: 1*P
Unique: 1
If a player joins the game, more cards will be added to the deck, but what happens if a player is eliminated from the game (due to inactivity or otherwise)? Some cards will be destroyed I presume, but are they taken from players hands? The playing field? The draw/discard piles?