NPC interaction would be the greatest. Really. The grrrrrrreastest thing ever!
There wasn't enough NPC interaction in JK2 where you slap and hit and jam.. or press... the use key on a partner, they look at you somehow and say something like: "Kyle!" or "Did you hear that?" or "They have cortosis arm!"
I would think there is NPC interaction in JK:JA since you pick any mission whenever you want.
He who fights with monsters he himself does not become a monster. When you gaze into the abyss the abyss also gazes into you.