I agree with this point specifically. I've been playing games for around 25 years - a lot of them; many of them major titles. I now find enemy AI in FPS games so utterly predictable there's little challenge, which is really frustrating. I beat Dishonored in around 10 hours, largely because I knew (even before I needed to use it) that a guard in an alerted state would "cool down" every time as long as I hid. That's exactly what happened. It really buggers up how much I'm drawn into a game when a guard finds a STACK of dead bodies, then 2 mins later sheaths his sword and strolls off on his merry way.
The knowledge of previous states of items seems like an absolute no-brainer to me. I'd find it really exciting. The first 2 Thief games scared the pants off me when I'd be hiding in the dark and a guard would spot a torch I'd blown out and get suspicious and start hunting me out. I really loved that and I'm not sure I've ever really experienced it properly again.