I don't think ethereum will replace bitcoin this year. but I believe the ethereum will be a bitcoin rival. if it sees its function, ethereum has more than bitcoin. bitcoin becomes number 1 because of the crypto currency pioneer. but only serves as an investment and buying and selling.
Obviously Ethereum has more functionalities than Bitcoin, since it is a newer coin (It was released in 2015). But at the same time, a number of new coins are getting created, which are even more advanced than ETH as far as the technology is concerned.