Why is it not more common to implement anti-cheat on the server instead of the client? Is that not more secure? Couldn’t the server just check what vision a player should have and not provide any other information to prevent wallhacks or maphacks? Or check how fast it is possible to move to prevent speedhacks? Aimbot is a bit harder to detect I guess but what about the other ones?
Depends what you mean by wall hacking I guess. Shooting through a wall should not be possible by your proposed method, and it could be expanded to prevent the player moving through walls also.
Seeing through walls though is a different matter. How does the server know if I have rendered an opaque wall or not?
Personally I see anticheat as a problem to be solved socially, not technically. Just let people vote to kick, and anyone who is generally accepted to be hacking will be kicked. No need for invasive Spyware.
This system is easy to abuse, and historically when implemented will be abused.