This prevents cheesing the system by moving all the way past the enemy before they even get their turn and are allowed look around
That is exactly the idea ...
I'm proposing something slightly different just adding a hearing radius. If Larian added a (smaller) hearing radius but still had the vision cone, then you could still pause time to sneak PAST (staying ~4m away) a patrol while they're frozen in time as long as you stay out of their hearing circle. Which is somewhat exploiting the turn-based nature of the game - that enemies don't move until it is their turn.
My suggestion is that enemies have only Notice Radius while in turn based mode, but rely on a larger vision cone and smaller hearing radius while in real-time and moving about. Alternately, they could still have the vision cone + hearing radius in TB, but maybe they also get disadvantage on a perception checks out to 2x their hearing radius. Basically I want to eliminate the situation where characters can sneak past (again, not getting right next to) an enemy without making a successful stealth vs perception check.
