She stealth kills people on crushing too but it's usually some far away guy who's not even posing a threat to us, and It's blatantly just for my visual benefit, not like she's thought about it strategically. Don't think there is marking on crushing as she hasn't marked anyone for me so far.
She's helpful sometimes but more often than not she's just watching or pretending to be busy taking the odd shot at the odd enemy. I've even had it when I've been out of ammo, there's like 3 enemies left and she's just stood by a door waiting for me to kill them, even though she has ammo.
EDIT: If enemies only ignored her when her stealth failed that would be ok as i don't want to be punished as a player for the AI not stealthing well enough but this sh*t is happening when neither of us are in stealth mode and we're both running towards alert enemies. It's just not good enough and in 2017, playing on a PS4 on the hardest possible difficulty i rightfully expect more from the AI department.
ANOTHER EDIT: Playing this mission where i have to take down an Armored vehicle with C4 and an RPG. 3 direct hits with C4 and 1 direct hit with an RPG and this things still moving around, even though she said "hah, not so tough now are you?"
C'monnnn man, haha. Just stupid.
Think I've gone off gaming which is sad. Every game I play has awful AI. it doesn't matter if the game has 4k graphics and 60fps if the NPCs still behave like It's 2007. I barely even play Battlefield anymore although I do manage to play that from time to time. It seems hard mode now days on any game basically means the same AI as easy mode but everything is a bullet/explosion sponge, or maybe their aim is better and you have your health nerfed. On it's own that is NOT the right way to make a game hard.
If you're reading this and thinking damn, this game sounds sh*t, the AI sounds awful, just ignore me, the games probably really good, Uncharted titles are high quality I'm just finding it harder to let sh*t slide in my old age. I think each generation of console gets less impressive as time goes by, wish it was like goin from Nintendo 64 to PS1 or PS1 to PS2.