Anything that simulates a 2Tc should not be cheap like the cost of the dock. I think I should make a thread dedicated to that topic.
https://www.reddit.com/r/aoe4/comments/1d6idw4/what_do_you_dislike_about_water/
You can increase the hp of the dock but it increases its cost significantly, Abasid has had the dock at half the cost and it is not the best in water, so for what reason is it cheap? It only allows those who have better units to be abused in the early game.