Hide/Stealth...
im very sure Larian is checking how we alpha their game, its what this phase is for after all... and the hiding or sight cone isnt the issue... the lacking part is the 360 sound, or memory of the targets... alot of these problems can be fixed, with simple AI changes...

Like AI was attacked, have no target, look 360 around, head in direction of sound, head in direction of attack...

That will fix most of the issues, but also opens up combos, for example one rogue attacks, while another rogue places a minor illusion as decoy...