For the past week or so, I have been toying with decks that have a very different structure from my usual -- decks that use only one copy of each card. Decks using this format have proven surprisingly effective as well as instructive, hence this post to encourage others to try it!
I have always used two factions (having sufficient numbers of powerful cards becomes an issues otherwise), and I do pay attention to various ratios that keep a deck balanced -- I do count my minions, make sure I have sufficient cards suitable for an initial 3 power move, and try to achieve power cost mixtures that don't waste a lot of power. Otherwise I pick cards I like and avoid cards (such as inferno, psychic vortex, ravager) that are hard to use effectively. I don't look for specific combinations as the probability of getting them to arise is not good.
I have found that playing these decks requires a lot of innovation -- I am finding combos I had previously not considered, I am finding unexpected uses for many cards, and have discovered incredible value of holding diverse cards when responding to threats. And playing these decks effectively is a fun intellectual challenge -- far more so than my standard combination based deck. The playing strategy is just richer.
I must admit, I don't think these decks would stand up to my best decks, but most are very good. I encourage players to give it a try.
You raise a valid and useful point. For strength of playing options having a variety of cards in hand is most important. And it can be influenced by how one plays. But it is certainly more influenced by the mix of cards in the deck.
And there are times when a mix of cards on the board is also useful. Four darkling assassins are more vulnerable to forked lightning and uncontinue than a mixture of units. And would you prefer two null wands, two spell books, or one of each on the board?
There certainly are advantages to multiple copies of cards in a deck, advantages that probably more than offset advantages of one of each type decks. The point of this column is that the latter can be more viable than one might expect, and are excellent learning tools.