I was testing this a lot specifically to get footage. Here's what I've found:
- The AI is shooting randomly when they wallbang, with maybe some idea of where you are. If they hit you, it seems to be fairly random. The problem I think is the frequency with which they go for wallbangs. Pretty much every suspect attempts to shoot you through cover if they lose sight, which seems unrealistic and leads to a lot of death and injury from things you can't see. Which leads me to...
- Windows. I think they're an important gameplay mechanic and shouldn't all be covered, but they certainly pose some problems. It seems like suspects have perfect visibility through them, while for the player they range from "somewhat clear" to "fully opaque" and so they to give the suspects a huge advantage. This is really obvious on Valley of Dolls where just getting close to window while you're inside can instantly draw the fire from guards outside, which you often can't see for a variety of reasons. In real life, especially on a bright map like Valley, it should be easy to see out but difficult to see in, based on how light works. Suspects should never see you instantly through what should be a heavily reflective/glared window, and actually you should be able to see them before they see you if you're looking out. For night maps, this effect would generally be reversed if there are lights on inside the building.
- Also, small gaps. Having just played Valley, the major problem areas seem to be the blinds, the outdoor garden buildings (the ones made of horizontal slats) and the stairs in the open area next to the pool (the ones that you can see through). On other levels, I think shelving has been a bit frustrating and there's definitely some other problem areas I'm not remembering. I'll add them if I think of them.
I think dying to wallbangs and enemies you can't see is a frustrating mechanic, even if it's realistic. It should be possible and happen sometimes, but it should be a lot rarer than it currently is. Since this is a game of angles, I think it's important to have many angles, windows, doors, halls, etc. and they shouldn't all be easily covered. Despite my complaints about the windows on Valley, they add a lot to the level and force you to think a lot more - like how you can seen on the left balcony from the fitness room. I didn't even realize this until I got shot from there, but this is totally fine and adds to the challenge. This is really how the game should work - Dying to stuff you should have seen, not stuff you couldn't see.
Edit:
And just to add to this, I think some ability to adjust the AI difficulty would be really welcomed. Not everyone is at the same skill or maybe they don't have a full 5-person team, but when you do have 5 people who know what they're doing it should still be a challenge. I know the level scenarios are supposed to be how you choose the difficulty but even the "easiest" ones can be a serious challenge with only 2 guys or new players. Just a slight reduction in response time would be all that's needed to effectively reduce the difficulty, maybe an adjustment in suspect equipment too.