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.