How do you make a game with all-human protagonists where a headshot isn't (nearly) an instant kill every time? Or at the very least severely incapacitating and putting-out-of-commission?
Depending on the tech level, helmets help. Or you could make the enemies duck or move head away to take glancing shots so that it's not instant kill. If freaky cybernetics are allowed, then stuff like having a metal skull works wonders. Or having a secondary brain hidden in the torso if the target is crazy enough.
He was speaking in the context of manual aim, where you can pretty much target the head all the time you want; heck, even go hit the face/eyes if the damage model is that detailed. Even if the target is behind, a lot of the time the head might be exposed
(or in fact be the only thing that's exposed). I think it's a good question, and a lot of the games just devolve into headshots galore after the initial to-hit problems are solved (e.g. the notorious case of Fallout, but even Jagged Alliance 2 wasn't free of this problem once you got your hand on some scopes). Not sure if it's worth going out of your way to try and solve this, with a sorta-realistic approach to firefights, every hit from a rifle cartridge should be enough to ruin one's day, even if it doesn't penetrate body armor, it should send the recipient to the ground.
Granted, body armor might have turned a lethal wound into a bruise, but that still puts you out of the fight. Bottom line is, awareness, positioning and who hot first should be the decisive factor instead of the ability to tank hits.
Still, it's not desirable for headshot to be the default move everytime, but I think it's a matter of fudging the numbers on the to-hit chances, so that it becomes a gamble and that center-of-mass shot continues to be the preferred safe bet,
nevermind quicker to line up. I think it can be made to work even with PP's targeting system - the head will always be a small target, too small to be covered by the entire targeting reticle. I think this is how PP implements in currently,
a lot of the time the default shot placement will already give you optimal damage output, so might as well save yourself the time.
This leaves two problems to solve, burst fire and close range shots. It is arguable if burst fire should even be targetable at all (while it's not inconceivable to do so, might be undesirable for balance),
even then, it might be less of an issue because if you want to saturate something with lead, center of mass gives you higher chance to hit, unless we're talking suppressive fire.
On the other hand, CQB is the natural environment where I would expect intentional (or accidental) headshots to happen a lot more, so it might be so there isn't anything to fix here as long
as engagement ranges are kept realistic (a lot of games and media in general tend to have shootouts happening at too short distances) and reaction time is emphasized over precision. This can be hard to pull off believably in turn based,
but RTwP can similate it rather nicely (see: 7.62 High Caliber and UFO After___). I love turn based with all my heart,
but I have to concede that it has its limitations when it comes to realistic firefight simulation.