I've played the game since day one, at that point there was a lot of complaints that the game was too hard. I could understand their point to some degree with specific monster in open world. The ones i avoided most was Harvesters, to me they were mini-bosses. But what i liked most at that time was that the story-bosses often had some mechanis to them and was bulky enough that you couldnt just ignore it and power through. I've played through the same vanilly quests later on and now they barely get through their evil monologue before they're dead. With all the down tuning and power-creep there is absolutely no challenge what so ever, every monster becomes the same as you wont even have time to notice their differences. Even if the story-mode bosses in the later chapters have been bulkier they are still very much just tank and spank. The risk of dying is zero.

Heck i even walked around with my character with nothing else on but a weapon and i barely noticed any difference.

So i was thinking about if it would be possible to set a personal difficulty to your character. Which could work even in an open-world environment by applying debuffs of different strenghts on yourself, like:

+50% / 100% / 150% More damage taken.
-25% / 50% Less damage delt.

(For me personally i wouldnt mind just having the extra difficulty, but one could reward those that do with a small extra gain of xp for example.)

I dont know how solo content can easily we changed but there you could maybe add some other additionally type of difficulties which wouldnt be possible in an open world. Lke:

* Stronger tier monsters.
* Bigger spawn groups.
* Insane story-mode bosses.

I love the game but i often get bored with it and taking longer breaks before i return. At this point i barely consider the open-world questing a game anymore but an interactive picture book.