The new water terrains are not working well with Questdog's alternate terrains. They are bleeding into each other in areas. Besides which the high contrast is making me ill.
I will reduce the luminocity of the coast in next update; but you might consider adding an artdefines_terrain.xml to the folder you have Questdog's alternate terrains in, that would be adjusted to make coast use its texture files.
trenches close to coast would create some graphical oddities worthy of notice but generally no problem in doing what you did; nothing that can break the game .What i did with my Current game was go to the Editor and added a border of Continental Shelf around the Coasts (I Assume I'm not causing Problems doing such)
Technically the color of all the coast are currently stemming from the water plane and not from the two terrain specific textures. changing the color of the water without changing the color of the beach equally is very difficult due to the way one terrain textures covers 4 tiles with its center in the corner of a tile and another has 30 different 32x32 areas that gets picked according to how many of the same terrain are around a corner and this one only covers 1/4 of four tiles and decides the transparency of both textures. I am currently experimenting with adding greenish color to the tropical coast but it won't go all the way out to the sea behind; this would lead to a third water color between the tropical coast green and the sea's coloration.I must say the Coasts could get a Tad more towards Cyan/Greenish/Blueish, the Artic Coast is good, but the Rest idk, Might just be my Personal taste
Yeah, I'm working on it.I Did notice Some of the Terrains Bleed into each other making things weird to look at, But that's something you should just test for yourself