ETH will reach $2500 when bitcoin does to $100k. I don't see ETH going to $2500 in the next few years unless bitcoin goes parabolic. Too many ICOs are selling ETH which will depress its price for some time. ETH is a good token but it needs to consolidate above $1000 before it can go to $2500.
it depends on how the alts will remain tied to bitcoin in the next few years. I really dont see eth reach 2500 this year or next year, but maybe in a few years the relationship between BTC and the alts will have changed completely, with bitcoin at 50K and less than 30% dominance