Deck building is about synergy. 30 cards deck with 15-20 types of different cards, what synergy you have? Then again, it would also depends on theme, strategy and type of decks
Unless you use only the minimum 20 cards deck. Plus I don't say to use 15-20 different card, I said only two copy for every useful card you have. If you made it too thin, you can add staples too. Beside it is very economic, that way you can have more various card at starting hand, so it's more synergizing than two same card at the same time while you only need one.
Look up KOG decks, almost every one uses multiple cards at 3 each. Seldom have a I seen a KOG not using 3 of multiple cards...actually, off the top of my head, I cannot think of any at all...unless someone got lucky and KOG'd with an unga bunga beater.
Anonymous
RetardedF2P
