What stealth games? There hasn't been popular light based stealth games since Splinter Cell. Nowadays, what counts as "hidden" is so much more clear than it ever was in Splinter Cell.

e.g. You can see all enemies thru walls with X-Ray vision, and they have a status indicator hovering above their head that tells you if the enemy can see you or not. Tall grass makes you invisible, guaranteed. The games were dumbed down long before ray-traced lighting came along.