There should be randomly generated temples that you can unlock with boss trophies

I think something that the game is sorely lacking is massive unique POIs that give the areas of the world more importance past just resource extraction and bosses. When playing the game it gets hard to become attached to any specific area of the world, as aside from biomes containing bosses, most biomes are generally the same in what they contain. Once the player knows what all biomes could contain, the only incentive to explore becomes just gaining resources, but if you know there's a possibility a rare temple could be found, it incentivizes exploring as many land masses as possible to find.

we came close-ish to temples with things like the Infested citadels, or even Frost Caves but I would want something that is more unique and not tied to one specific biome (there would be one of these for each biome, making 6 total)

These could act as a tough gauntlet dungeons, with the reward being a major upgrade to your Forsaken abilities (increased effects, duration, lower cool down, etc.)

Imagine if you will:

– Each boss had a specific temple that can only be unlocked with that boss' trophy.

– There would be only one of each of these temples through out any given world, making them both rare and unique

– These temples would have unique features and be close to, or surrounded by unique generated features. (Like the one for Moder hovering slightly in the air above the tallest mountain in your world, or a temple in the plains that had a massive fulling city built around it, etc.)

– In the temples themselves there could be unique biome themed mini bosses, traps, unique loot, etc

– They would ultimately act as a form of mastery over each biome's unique challenges

TLDR; Massive temples for each boss that only spawn in one specific place (like the Trader does) and are built near a unique biome related feature like the tallest mountain in your world, a giant swamp graveyard, massive fulling settlement, abandoned dverger mine, etc. and their purpose would be to permanently upgrade the forsaken ability, giving you an incentive that isn't resource related. They would contain challenges and mini bosses.