Well, instead of looking for a health pack you can just sit behind cover waiting for your health to regenerate.
Well, most of the time, you actually know where that last healthpack was and dont need to go looking. Two titles I remember in particular when talking about this funny thing common to most (older) shooters are Goldeneye and Halflife 1. The game usually breaks down a bit into several encounters with breaks in between. I think that's also a somewhat accepted technique to make the action feel more tense.
Sure, there are exceptions, (tank and train levels in goldeneye for instance) and there everythign you said holds true. But for the general flow of all the shooters I played since the first wolfenstein I remember this backtracking thing to be true. It's a part of the nature of every gamer of ye olden days, I'd say. We'd been stashing mushrooms in Super Mario Bros if the game allowed us to walk backwards, I tell ye.
But still, this leads us to:
Say you screw up and get hit allot but not quite killed?
three options:
1) You backtrack to the last pack (rhyme not intended) which is not even a simulated success, one of the major reasons to actually play video games. It's, mostly, just backtracking and wasting time. And playing games might be considered wasting time already...
2) You dont know any locations of healthpacks, but you manage to find a new one. Yay! cheap thrill, running around with 1hp! (Not so bad, actually...)
3) You get hurt along the way and die. For modern shooters that means level restart or reload. Big whoopin deal.
Or how about this? Take a peak out and shoot someone, get hit slightly, and duck back behind cover, waiting for health to regenerate before popping up again. Do this 15 times, thus surviving enough damage to kill you twice over by simply not taking it all at once.
This is just a case of very, very bad AI and/or implementation of the regeneration system. The AI usually has the upper hand, numberwise, so it should try to flush you out of cover, either with grenades or a rush from two sides. But there is still the case of a shootout between the player and that last NPC, in which even a good AI should decide not to flank the player. And not only for that eventuality the health of the player just should not regenerate as long as somebody is shooting on them, regardless of whether they miss or hit.
A lot of finetuning also can be done by the quickness of the regeneration. Generally I'd say the most appealing way is to have a timer since the last hostilities, let's say 30 seconds or so, that is pretty long for the ADS and SAS guys
And then you just start of with a very, very weak regeneration, just enough to make the player notice and reward him for waiting, slowly but exponentially ramp that regeneration up to a point where it becomes useful.
Generally, shooters that actually used to use medpacks and a hitpoint system could benefit from regenerating health by "streamlining the gameplay".
Seriously, I'm a fan of roguelikes, I'm all for permadeath (what would that mean for "Goldeneye"? The cartdridge self destructs so you have to go and buy another one?) and realistic injury systems. But there is deffo a style of shooter that just benefits, if pulled of properly.