There is no doubt that Ethereum is the most promising altcoin. Ethereum lost more than 80% of its value in 2018, but it is undeniable that it is still worth investing. If I have to invest in an altcoin now, then I only will choose Ethereum!
Not to mention it didn't lose that much because of worse fundamentals, it lost because ICO-ers dumped.
There's not much to dump in 2019.