lots and lots of tiny little islands all covered in thick fog, filled with mobs that will cleave your boat in half in 1 swing, the ship is too big to replace it, dying in mistlands makes corpse running hell, since you cant see where you are going or what 1-shotting mob is infront of you, mobs that deal deadly damage even with your best armor and good food buffs.
Its an annoying danger from the seeker mobs, the gjall is ok, but the seekers seem to spawn more lvl 2's than lvl 1's, not to mention the knockback they do, sometimes they knock you so far back you fly into the sea and you might be low on stamina, so you nearly drown on the way back, if you can even get up from the water, cause the slopes of the islands are steep, the dwarves definitely have problems getting up from the water, once they fall, they never get back up, and then the seekers can just do what they do until they die.

installing several mods took a massive weight off my shoulders, such as keeping everything on death, makes dying in mistlands less of a ♥♥♥♥♥, cause mistlands is a ♥♥♥♥♥.

I dont like mistlands. i think it needs to be cooked in the oven for a bit longer.
Plains was hard, but it was fair.
Mountains was hard, but it was fair.
Swamp was hard, but fair.

Mistlands on the other hand, spawns fuling berserkers that fly like deathsquitos, in the thickest fog imaginable (and thats even with the little whisp lamp)

Mistlands makes me lose interest in the game.