Or they could just make survival actually be hard.
My suggestions:
Food and water exist, make hunger/thirst part of the game.
Sleep is there, make sleep needed.
Ammo, stimpacks should have weight.
Radaway is FAR too easy to get, radiation is nearly pointless
Permanent radiation damage should exist if you allow yourself to absorb too many rads, again radiation is a joke in this game
Remove the hazmat suit, it trivializes radiation and shouldn't exist in this world
Ammo should be far, far more scarce. Melee should not be a choice, but a necessity. Guns should be used sparingly not like an arnold schwarzenegger movie like it is now. There are no factories producing boxes of ammo anymore.
Stealth is far too powerful, there's no need to add things like not activating mines and not tripping traps. in fact,the game would be much better if stealth were removed.
Feel free to add your own.