I'm not sure you realize, but by balanced, he was referring to the card game being moderately reasonable - not having so many overpowered (or perhaps conversely, underpowered, though this usually doesn't occur) cards / combos. An unbalanced card game is not ideal for the vast majority of players. Not many people like it, myself included.
You don't play Yugioh, but the current format is a load of crap in my opinion. Turn one Shien, turn one Royal Tribute, and just back row spam in general. 90% of the time, the person who wins the dice roll will win the match. There is just such a huge advantage of going first. In fact, the world champion won because he won the dice roll - I am not kidding. I lost out on my invite to this year's European championships because I lost the dice roll on the final round. Not to mention the amount of busted ass cards that are in our current pool. Reborn Tengu, Hyper Librarian, Brionac and Trishula to name the main culprits. These cards ESPECIALLY TENGUE AND LIBRARIAN, should never have been made. They are so bloody stupid and they truly ruin the game. This is the main reason why I am taking it easy with Yugioh for a while and sticking to the Pokemon TCG for a bit. I do not enjoy a significantly unbalanced format. So yeah, balance in a card game is incredibly important.