Was it intentional to have AI companions in plain sight, but you still not being spotted?
That was absolutely intentional, and it was a very hard decision to make. As Sessler and a few other reviews pointed out, the alternative would be extremely infuriating. We are trying to make a game where stealth is an important aspect, and we knew we wouldn’t be able to guarantee the buddy AI would be able to stay hidden as well as the player. If the buddies were seen by enemies, it would be extremely frustrating.
The buddy AI was actually what I have spent the last four months or so writing, and I think we did a good job of making them seem believable. Ellie will stick in cover with you and hunker under your protective arm, and she is good at keeping up with you.
The best thing is that because the AI is emergent, the playthroughs will be different for everyone, and different on successive playthroughs.
Is the balance of power AI system still in the game?
Yes, we managed to get a lot of reactivity in the AI. If they out number you they will be a lot more confident, if you out gun them they will be a lot more cautious, etc. They will hide from you, flank you, wait you out, flush you out, and coordinate to attack you.
There are a lot of systems running behind the scenes which make it all work, including some really neat environmental analysis, an upgraded pathfinding system, and ultimately some carefully hand crafted and tuned behavioural systems.
Why did you decide to make enemies ignore Ellie?
Ellie can still die, just if the player is trying to be stealthy they won’t see her. As I said elsewhere, we made this choice because it would be frustrating if a player had stealth broken by Ellie being seen.