[aezart]

Splinter Cell and Thief are the only series I'm familiar with that actually have light and shadow based stealth. Everything else is all hiding around corners or inside/under furniture, like Metal Gear Solid.

The Splinter Cell lighting stuff never made much sense anyway, since you'd be perfectly fine if you were standing in a shadowy patch while making a clear silhouette on the illuminated wall behind you.

The strangest misbehavior moment I remember from the first game was like this: There were two NPCs working on computers in a dark room. Behind them was an open door to an illuminated office. I walked into the office and shut the door, they didn't notice there was suddenly no light coming through. I turned off the office light, no reaction. I opened the door again, and then they noticed the office light had gone out.

[keyringlight]

One of the biggest challenges with computer UIs is how you convey information to a user, and that goes especially for games where players often can't take much time to analyze complexity, and it gets boiled down into a light gem indicator. One of the things I really love about the Thief games is how intuitive they are because they're mostly relying on sight/sound senses, you can relate to how the guards/defenses are going to sense you because it's how you would detect someone. If you're noisy you know what will happen next, and the guards are extremely vocal in telling you their state.

Going beyond that simplicity to account for other factors you could technically improve the simulation with is where I'm not sure it makes it more fun. Ultimately a mission needs to be conquerable, how far can you go making it more challenging and leave space for the player to push through while remaining plausible. Silhouette, different areas of your body being lit/unlit, whether movement speed of a lit/partially lit person affects detection makes a difference, guards having long term memory and adapting to half of them - they all sound good but I'm not sure they'd actually be rewarding to players and the development studio that implemented them. How do you 'tell the story' of a guard that spots your shape, knows you're sneaking around acts accordingly to take you by surprise and ends your game.

Similar with armor systems in a lot of games, we can probably simulate a lot of coverage/protection and the impact on mobility, that characters ability to fight with various weaponry because of what they wear, injuries, and so on, but for most games it gets abstracted into categories or points. Even if computation challenges of physically simulating that were overcome for dozens of characters in a fight, how do you convey all the consequences to the player to suggest how they can change things.

[pirates]

Newer Metal Gear Solid games definitely have light and dark as an element of stealth. In MGSV playing at night is basically easy mode.

[Mashimo]

I'm not 100% sure, but I think Oblivion also had shadow based stealth.