i dont know what you use as a measure to say eth has disappoint you this year but o me it has done a great as it move from $80 to over $200+ and all you could say is this well we know how this work than each other but i can tell you that this year has been a good one for eth and the future is also bright for next move.
Many investors expect eth to rise just like the growth of btc this year but the progress is not really satisfying for some. It takes time before we can see a huge recovery for eth and other altcoins but we dont know when it will happen.
But as long as you believe in eth as a good coin then look forward for the next bull run and be patient. In time we can see major changes in altcoins.