A great way to give players a sense of danger and importance of stealth.
Is to have consequences for getting into a open conflict for to long.

The unidad military faction in wildlands had exactly this.
If you were unable to eliminate a patrol of unidad in time (a few seconds) that had discovered the players.
Large amounts of enemies would show up and hunt down players who would not choose to flee.

It was a great feature that really drove that feeling of danger that came with knowing that if you're not careful and fight for to long, that you can be sure that a overwhelming number of enemies and attack helicopters are on the way.

If this could be added bact to the game it would be a great improvement.

Thank you for reading.