Dude, I just explore an entire island with my friend, the island was 99% Mistland (a small piece of Plains in the corner) we found 4 Dvergr roaming around, but 0 constructions... We explore the entire island, even placed more than 60 Wisp Torches around. Today we'll go to another island to try again.

My problem here is the design of those POIs. In the other biome you are able to spot a POI (point of interest) from afar because it's completely different from the biome itself... Here in Mistlands, even without the fog, everything is almost the same thing as the biome... If you find an ancient sword/armor you won't know if you really find an ancient sword/armor or a skeleton until you get really close.

The same with the structures, in our first island we found a Dvergr pier and a Dvergr tower, both look alike too much, at the time we didn't know what it was and what does what, but now that I know I have to explore a tower to find the dungeon I see how a player can be confused... Now you include the fog to make everything even worst (I know, there are mods that remove the fog, but it's part of the mechanic, I don't want to ruin my first experience with mods that can change my game play that much)