yeah that must be it because they are wearing 12 inch armor plates.
I have spent MANY hours playing through STALKER and Clear Sky and many of the enemies can pick you off with ease. at the same time they basically laugh at the dozens of rounds I fire at them even when I am much closer. I get so tired of a few people acting like everyone else is just too stupid to play the game. the game is really unbalanced in many areas and the AI can be ridiculously good sharpshooters no matter the conditions or distance.
I'm not disagreeing about the fact that most Stalkers in the game seem to take too many shots, nor about the fact that the A.I in all three Stalker games can reach both extremes (being barely existent, to being cheating Gods). But ALL the people I've seen complain about the Stalker games never made it past Cordon in SoC, or the Swamp in Clear Sky. Trying to judge Stalker after experiencing the very harsh early moments is doing themselves a disservice.
Once they get their hands on a Merc or Reinforced Suit, or a VSS Vintorez and fire two or three shots at a fully-armored Stalker to take him down they'll cry with joy, but they need to work their way there. Stalker doesn't feed the player like 90% of the fast-food FPS games we've been forced to play since the past couple of years, Stalker games are survival-horror games, your initial goal is to survive, and then later on you can start acting like you're somebody. With something like a SEVA Suit or an Exoskeleton players finally get to experience the other side of the medal and they become the ones who can seemingly take full clips of 'x', 'y' and 'z' weapons without much problem.
Granted, all three Stalker games have issues with A.I and overall game balance, but none of the issues in the game play much of a role against the player once the player actually tries to get through the initial mess and make its way to the powerful items. The only problem with that is that once you get the point where you're geared for full scale war the game is pretty much dealt with. That was fixed to some extent in Clear Sky, where you can get very good items early enough. I have yet to complete CoP so I can't comment on that one but the general balance in CoP is far better than it was in SoC from what I've experienced myself (and without modifications implied).
Overall, anyhow, Stalker games aren't easy, it's not for everyone, definitely. It's a love or hate relationship for a lot of players, I've rarely seen players claiming that Stalker games are "alright", it's usually either "very good" or "terribad". If there's players out there having issues with the balance in any of the three games then I'd recommend them checking for mods, although most of them make the game unstable (and it's not like it's entirely stable to start with by default, especially not SoC). I haven't actually played any of the three Stalkers in months, but I absolutely loved SoC which I completed two times, the first time being under vanilla settings (no mods), the second time months later with the AMK mod, but it was a pain since it kept crashing, but I still stubbornly made it to the end over a long period of time since the mod was so fun (but made the game a nightmare in terms of difficulty).