As BTC has dramatically increased in popularity it's becoming harder and harder to quickly, and cheaply, send BTC between wallets and exchanges.
It also feels like BTC is a single point of failure as so many cryptocurrencies are linked to Bitcoin that when BTC drops in price it frequently takes the rest of the market down along with it.
I'd love there to be more pair options whether that's ETH or LTC to help facilitate the movement of money within the crypto-economy.