Look, price of anything can go anywhere and anytime. So it is not possible to predict the price of ETH in 2018. But in my opinion, the current market situation indicates that its price will be $1500-$2000. Though I am not fully sure.
Yeah, and that is just how market generally is and there is absolutely no way we can assume exactly what the future holds for any coin. Ethereum even though it showed some pretty huge bullish momentum recently does not mean that we cannot still get back to a downtrend. I have been bullish on Ethereum but I still follow trend most of the time as the market can be full of surprises and this year may be filled with one.