I don't see any need to put rares in, but I'm all for better and/or bigger starter decks. Deckbuilding is definitely part of the fun, but when it takes a lot of time and electrum to get any real number or variety of cards, it's not an incentive to play around with decks and build your own deck -- it's an incentive to go look up someone else's deck in the forums and focus on building and using only that deck.