Another thing to note is that you take damage rather quickly in Vanquish and don't have a lot of HP. A medkit restoring only 50% HP in this case would be pointless
That's hardly a compelling argument in favor of regenerating health. Most games with regenerating health have fragile protagonists, because at some point the developers realize that with the absence of health management, it's the only way to introduce some modicum of challenge (albeit not a very interesting kind of challenge). Adam Jensen for example instantly dies from a 3-foot fall without the Icarus landing augmentation. Vanquish doesn't have regenerating health because the player character is fragile, they made the player character fragile to justify the use of regenerating health.
The player is made fragile because you have no business walking around being able to tank bullets when you should be sliding away from bullets instead, hence why you die so fast. Especially because like I said before, Vanquish doesn't play the long-term game, and with medkits you'd be in a critical state for longer than need be as you're desperately trying to find your way back to a piece of cover which has a medkit behind it, slowing the game down as you're trying to heal yourself. There's not a whole lot health management would add to Vanquish, and more it would diminish. If you had more health, then you could bruteforce your way through more by tanking damage and playing the popamole game. Whereas with less you'll be forced back into cover more often, and if you want to
go fast without receiving critical damage you'll have to think outside the box.
Having to twiddle thumbs around health management would slow the game down, which is exactly the very opposite Vanquish is going for. It'd make things more 'tactical', but
this is not that kind of game. It's about going fast in the here and now without having to worry what happens in the future. If you want to make a better case for why health management would improve Vanquish, you should explain how it would improve
what Vanquish is going for. If the incorporation of health management would break several existing elements and would have to involve changing several key aspects of the game to the point where it can't be called the same game anymore, it isn't necessarily improved, but just changed.
Health regen works in Vanquish because you're given enough tools to avoid taking damage (cigars, speed, nades, boost canceling, boosting from cover to cover to avoid line of fire, etc.) through skill, whereas you're forced back into cover if you take too much damage or are too zealous on your booster energy. It's not a patchwork solution for having hitscan enemies when you can still avoid taking damage entirely through learning the game. As Vanquish is about going fast, you don't really want to waste time scouring the level for medkits. Having regenerating health keeps the downtime brief so you can be on your way ASAP. When you consider that Vanquish grades you on how fast you complete levels, with taking damage to a critical degree serving as a time penalty by forcing you to recover by forcefully emptying your booster.
The fact that many of the tools you list rely on the use of cover doesn't really help your argument. Vanquish is a game very much built around regenerating resources, both your health and your ability to rocket slide. Like most other cover shooters, you don't have a lot of mobility either, you can't jump and you can only rocket slide for a few seconds before you have to wait for the bar to refill or the suit to stop overheating, and the default movement speed is very sluggish. In many respects, Vanquish isn't very different from other cover-based shooters with regenerating health.
Many other cover-based shooters don't allow you to offset incurring damage through mobility like Vanquish can. In other cover shooters, taking damage is practically a binary state. It's almost inevitable if you peek. Even though energy regenerates, energy management is still an important part of the game. As suit energy allows you to perform all kinds of wacky tricks to be more aggressive, it becomes important to manage as abusing it will overheat you and leave you defenseless. You then might ask why you might as well not add health management to the mix, and it's because your health is strongly tied to your suit energy already.
If you're out of energy, you're a sitting duck unless you get back into cover or kill the remaining enemies before they can shoot you. If your health is critical, slow-mo is triggered automatically and suit energy will automatically deplete, giving you a few seconds in slow-motion to plan how you're going to defend yourself instead of getting insta-killed because of a hitscan barrage like in most other games, but after that you're out of juice and need to plan ahead. Health and energy are already strongly intertwined. But it doesn't take that long to replenish either, so unless you're getting hit all the time you can boost and punch more often and have a nice fast day. You're not weighing the cost of offense by your remaining health, but by your suit energy. If health was a limited resource, then there'd be less opportunity to use your suit energy because healing yourself takes priority. Though I agree melee attacks consuming all your energy is pretty gay.
Since we're already on the topic of Mark Brown:
And being graded on how long you take to complete levels is an artificial crutch and certainly not something that justifies the use of regenerating health. If you want to incentivize and reward players for playing a certain way, you should do it through the gameplay mechanics, not some meta layer like a ranking system. For example, Doom's highest difficulty naturally rewards playing fast, because monsters will continually respawn, will move and attack faster and health and ammo pickups are limited, so the player has no choice but to move at a breakneck pace.
But Vanquish does the same thing. It's much easier, faster, and more engaging to play like this:
Besides, if the game flat out tells you through your score and end-stage ranking that you fucking suck, isn't that enough to know there's still plenty of room for improvement? Most Platinum usually give you a clearly crappy Stone Award or a low rank if you stumble your way through, for which Vanquish is sadly the only exception to with its flat scores for which you don't know if you did good or bad. It doesn't affect gameplay besides grading your performance, but normally it should tell you there's more to the game if you know how to get high ranks. When faced with the question of being able to play Vanquish while looking cool or playing Vanquish like a generic cover shooter, I don't know why people
willingly choose the latter despite there being plenty of online footage of superplayers having to use next to no cover at all.
You argue too strongly from the position of classical euroshooters, where the presence of health and ammo management made sense and the levels were actually built around those ideas, whereas the levels in Vanquish simply aren't. There's no enemies in Vanquish who could chip away at your health, because there's just no place for them in the game as it is, which shouldn't be an inherent negative. Just like a RPG built around trash encounters dragging your party's resources down over time with limited resting available isn't necessarily superior over an RPG where encounters are always highly lethal, but you can always fully rest afterwards anyways. But then again health regen wasn't inhibitive to enemy design in Vanquish either. You get several from big robots with weak spots on their back encouraging mobility, enemies which act like mobile cover, more special mini-boss type of enemies, and several other mutators to prevent even the grunts from feeling stale.
Vanquish doesn't have much in the way of environmental hazards, because the environment and its enemies are built around messing with cover usage. So enemies will spam grenades like mad if you are behind cover, half-killed enemies will try to kamikaze you and force you to peek or run, some enemies have insta-kill projectile attacks which completely ignore cover, some cover can be destroyed, and in some parts of the game cover will actually randomly shift on or off.
"There's a lot to like about the nu-doom game"
Why would you watch past this? Flag for terrorism and move on.
I wouldn't say "a lot"
For example nuDoom happened to have the only good (decent) first-person shooter boss fights in the whole fucking history of first-person shooters
Hardly. The concept of traditional boss battles in an FPS is inherently stupid to begin with, and nuDoom merely continues that dumb tradition.
What is the greatest possible challenge in an FPS? It's aiming, or more specifically aiming at a target that's moving really fast and therefore hard to hit. What is the archetypal boss fight? It's a gigantic, slow-moving HP sponge, i.e. the easiest enemy to hit, not the hardest.
Unreal's Skaarj are more interesting to fight than 99% of FPS bosses, and they're not even bosses.
I don't disagree, but I was mostly referring to the fact that the bosses in nuDoom attack using special attacks you can actually dodge like in Ys, instead of having to solve a puzzle or hide behind cover. Which in some parts made the bosses more exciting to dodge than normal enemies.