The easy way: limit saves, long respawn times, other such annoyances. The player isn't fearing death really, they're just annoyed by it. Not allowing quicksaves can help a lot, but only if it's done well, sometimes checkpoint systems and such get cocked up badly by some devs.
The hard way: make the player connect with the character. This is really hard to do, and one of the games you gave as an example does it really well, I think: Red Orchestra 2. You want stuff like injury animations, screams of the dying, the gurgling of the dying drowning in their own blood, hardened soldiers screaming for mommy, bullets whizzing and snapping, loud and terrifying weapon sounds and impact effects. Suppression mechanisms help a ton, too, it can bring the player close to death without ending there immediately, giving them time to try to evade and react, while still suffering temporary negative effects from the experience. Animations are critical, since two visual/gameplay states (alive and perfectly healthy or ragdoll) don't really add much to realism. Also, a generally realistic game helps, but isn't necessary (see Dead Space, which is unrealistic, but very gruesome and horrifying when you die). Battlechatter will help, in RO2 hearing my soldier go from "DIE FOR STALIN COMRADES!" to whimpering "I don't want to be a hero" after taking a grazing hit really adds to the feeling of not wanting to die.
At one point in RO2, I had shot an attacking German in the chest as he came through the door, and I spent the next 30 or so seconds listening to his screams of pain as a pool of blood spread around him. Finally, he wheezed a death rattle and was silent. Not only did I feel bad about killing him, I became scared of my character ending up the same way. Better camera work and animations could make such experiences even more traumatic. Also, sometimes if you blow up a tank, you can hear the screams of people burning alive inside, which is pretty gruesome, and when you see your tank crew die it's brutal.
The real problem is how sterile death is in games. Make it bloody, violent and horrifying and gamers will stop treating it like math (5 kills for 1 death = 4 profit + 5 second wait time) and more like real life (I don't want to die or kill!). It's about the experience, not the math.
The hard way: make the player connect with the character. This is really hard to do, and one of the games you gave as an example does it really well, I think: Red Orchestra 2. You want stuff like injury animations, screams of the dying, the gurgling of the dying drowning in their own blood, hardened soldiers screaming for mommy, bullets whizzing and snapping, loud and terrifying weapon sounds and impact effects. Suppression mechanisms help a ton, too, it can bring the player close to death without ending there immediately, giving them time to try to evade and react, while still suffering temporary negative effects from the experience. Animations are critical, since two visual/gameplay states (alive and perfectly healthy or ragdoll) don't really add much to realism. Also, a generally realistic game helps, but isn't necessary (see Dead Space, which is unrealistic, but very gruesome and horrifying when you die). Battlechatter will help, in RO2 hearing my soldier go from "DIE FOR STALIN COMRADES!" to whimpering "I don't want to be a hero" after taking a grazing hit really adds to the feeling of not wanting to die.
At one point in RO2, I had shot an attacking German in the chest as he came through the door, and I spent the next 30 or so seconds listening to his screams of pain as a pool of blood spread around him. Finally, he wheezed a death rattle and was silent. Not only did I feel bad about killing him, I became scared of my character ending up the same way. Better camera work and animations could make such experiences even more traumatic. Also, sometimes if you blow up a tank, you can hear the screams of people burning alive inside, which is pretty gruesome, and when you see your tank crew die it's brutal.
The real problem is how sterile death is in games. Make it bloody, violent and horrifying and gamers will stop treating it like math (5 kills for 1 death = 4 profit + 5 second wait time) and more like real life (I don't want to die or kill!). It's about the experience, not the math.