It's the year of Bitcoin in my opinion because after 2017 Bitcoin just moved flat in the market. In my opinion, the year of Dogecoin is not suitable, because there are still many other Altcoins that have increased positively since the middle of this year. We also don't underestimate Dogecoin which can surprise the market because they can always make a difference.
Dogecoin or meme coins are full of surprises because it can pump very suddenly thats why it's speculative because if it can pump suddenly it can also get dumped suddenly but as I see this year, ETH already getting so high in price and I think this year the altcoin that grow so much is ETH.
Even if ADA has become the third market cap coin I think the market cap difference compared to ETH is still too big and maybe ADA is just replacing BSC in market cap while ETH is very bullish and can break the ATH anytime or it can be dumped again because market starting to become bearish.