Sneaking is op because you can start a battle with a sneak attack from Astarion and then the combat tracker is just Astarion and the enemies that saw him, or maybe only the little pillar of light that shows up.
Once Astarion gets locked into the combat tracker you can still maneuver everyone else around the enemies sight lines and get a few more alpha strikes in outside of the combat tracker. My paladin -- in full plate -- can walk right up to an enemy that's frozen in the combat tracker as long as he doesn't walk into the sight cone.
I beat dror, m, and gut in the goblin camp all without any of them taking any turns because I was able to alpha strike them into the dirt by just starting combat with the whole party sneaking, and then walking them right up outside of the combat tracker.
Is there a party that can really exploit this? Ranger, wolf barb, shadowharts +10 party sneak, and an assassin rogue? Just alpha strike everything.
Yeah, it's the "realism" thing that breaks the illusion that the enemies have any basic situational awareness.
The first thing most mammal type animals do when surprised or fear attack is look around and prick up their ears.
i reckon i've seen mice, rats, cats squirrels, dogs, sheep, and many more animals all do this type of thing just on hearing an unepexted noise or something., much less seeing someone shot or mysteriosy smashed with a dagger out of no where.