Outpost difficulty ratings should be adjusted based on performance statistics
Let me start by saying that I love this game and I want other people to be able to love it to.
It seems to me that a lot of frustration comes from raiders not knowing what to expect from the outposts they're choosing to raid. For example, a new player might complete a few "brutal" outposts easily and then die dozens of times in a "dangerous" outpost that's punching way above its weight class. On the other hand, someone might try to step up to "brutal" difficulty and instead find a free XP loot farm.
By adjusting the outposts difficulty rating periodically, based on victories/kills, the readability of the game would be dramatically improved. Most importantly, this would better allow new players to set their expectations. As it stands right now, the difficulties in all 3 categories vary wildly, to the extent that there are "brutal" outposts easier than "normal" ones and vice versa. I think an ideal UX would be that "normal" outposts should be consistently beatable in a couple tries for beginners, "dangerous" outposts should be suitable for people who like a bit of spice, and "brutal" should be for people who really want a no-holds-barred extreme challenge with tons of interweaving traps and guards. If the game can consistently make the 3 difficulties feel distinct, then I don't think nearly as many people will feel cheated by "impossible" outposts.
The only way I can see to really achieve this is by moving outposts up a difficulty if too many people are losing and down a difficulty if too many people are winning. The current system by quantity and variety of traps could still be used for a provisional difficulty rating, but without some kind of statistical adjustments it will always get too many wrong.