4Game

Mistlands is a biome that has the potential to be the best addition to the game by far, it's just unfortunately held back by a few core issues that are at least somewhat easy to fix.

Jagged terrain can be fun and challenging. Low visibility can be fun and challenging.
Both combined unfortunately result mostly in frustration specially if there are no tools to make these aspects more approachable.
The mist removal is extremely weak currently. Even if you can hear and see the enemies from a decent distance,  the terrain navigation and exploration is still just not fun unfortunately. The demister effect needs the range increased by 3x or 4x and preferably also ensure that the terrain generated has more open areas and not as many bodies of water and small chunks of land or islands.
For the jagged terrain we have the slowfall cape but we receive it so late during the progression that you are almost ready or ready to fight the Queen and leave the biome. Simple solutions would either be to get the cloak earlier or have a mead with the slowfall effect.
The terrain also exposes how weak valheim's combat is on slopes, which doesn't help at all.

Another problem is the progression. Having everything gated behind so many black cores also feels very bad because there are not enough sources for them or they don't seem to be common enough in the Infected Mines. After going through 4 mines for 4 Black Cores, the experience can leave a really bad taste in the mouth. Many solutions can be found here. Increased rate in dungeon generation, multiple added sources in outside dvergr locations, added in the dvergr boxes or add them as tradable items.
Sometimes you can end up seeing everything the biome has to offer without making even a single new piece of gear.
It would greatly improve the player experience if we could make the new gear early with which to fight these new threats.

Speaking of threats, we are now to my last point, the Dvergrs. They are friendly but you cannot trade with or recruit them. And moreover, you are supposed to kill them to get valuable items that actually unlock progression.
For this one, simply having them unfriendly straight away or add the 2 features above would really help with eliminating confusion. Maybe a mix of the 2 would be perfect, where some are going to attack you on sight, normal enemies, while others are friendly, you can trade with and maybe even recruit. This would encourage slowly scouting their encampments to find out which approach you should take.

Overall I'm not a fan of the Biome. The feeling, the aesthetics, the design of the enemies, the magic system, the new dungeons. All of it sounds amazing but unfortunately the points I made above in the list really makes it hard to enjoy it.