You claim multiple times that you want characters to have the ability to properly assess a situation
Well, here's where I think many combat systems go wrong: let's take the called shot to the head. You can't force that in every situation - it's only a good idea when you catch the enemy not guarding it. We're not simulating this detail in combat. The assessment of the situation is about other aspects of the scene.
As for PbtA, it abstracts some things away that I'd rather not have abstracted away. And for people who rather care about story and/or who look at combat as just a specific part of on-going story, it doing so is just fine.
Two things: Harnmaster is a red herring -- you don't care about designing for Harnmaster, so bringing it up as a counter-example is just chaff. Second, "trad" is doing a lot of work. Let's be clear, you're designing for 5e.
Hell, no. d100 >> d20.

Don't hate D&D either, it's an okay game, I occasionally play in its ruleset. These days in the form of Star Wars Saga ed.
Also, there's nothing in 5e that says you fire 2 arrows a round [...] but DW isn't a clueless guessing game on the part of the players.
True
If you climb, you use this set of rules for climbing which don't care about the overall fiction of the climb, just that if you climb this much you use this mechanic to make a succeed/failure check. That's not fiction and mechanics tightly coupled, it's just a process sim.
I find the difference between process and fiction artificial and you probably can't draw a good line between them. In trad games, fiction emerges from the interaction of elements. As soon as something changes in the world, you got story. Whether it's an interesting story or not is a different question.
But I am glad that you're acknowledging the difference in detail and abstraction level. There's a fork in the road here, which is: "I feel I am in the situation if we focus more on the big picture of the scene and its role in the overall story" versus "I feel I am in the situation if the scene is represented in detail in the mechanics". That's probably the diverging underlying philosophies between trad (or rather sim?) and narrative. And that's fine. I don't hate narrative, I merely wouldn't want it to be my daily bread-and-butter games.
But really fights against the idea of cinematic combats and is the direct reason that there are no good systems for cinematic combats in process sims.
That is not something I can agree to, I'm afraid. Speedy combat resolution is good but you're not going to be as fast as actual cinematic fight anyway. And then it becomes, once again, a matter of setting priorities - accurate sim of events versus speed.
What's the difference in 5e? Rhetorical question answer: none.
What's the difference in Shadowrun (+2 Defense), Dark Heresy (-20 BS), GURPS (complicated calculation), etc.? There's one and sometimes a significant one. This matters to some of us gamers out here. In fact, it matters to someof us, that the difference is not expressed in a generic handicap (like Disadvantage) but that different circumstances give different modifiers. Which, again, boils down to how much rules and detail-work you can stomach. But to some of us these modifiers makes the words of the GM alive when he declares: "The orc turns sideways and tries to reach cover but you can shoot before he reaches it." Without such specific modiers some of us don't feel really in the scene.
So far, you've shown very little understanding of other systems and how they work.
You've been arguing against a strawman in the last part of your reply, I'm afraid.
You can't get everything within 5e, for instance, because it's system prioritizes and incentivizes certain themes and design goals. Same with PbtA games: they do some things poorly that 5e does well.
There's a third category of gamers who are not fully happy with either D&D or Dungeon World. People who want detailed process instead but faithful to either realism or whatever genre/IP they try to recreate. These gamers didn't have much of a voice in recent years but they still do exist (I do count many fans of Shadowrun among them, btw).
I can enjoy everything from a hard-math sim wargame, to relatively abstract board games, to trad mechanics, to modern rpgs. They all have strengths and weaknesses for me.
Absolutely. 2 years ago I ran a Trail of Cthulhu one-shot which was better than any CoC adventure I had played till date. But that was mostly because of the uncompromising adherence to puritan Lovecraft, ending in a (more or less) hard-scripted TPK - the monster had no stats, it couldn't be defeated. Everyone had great fun dying or going insane!
While I agree with your general sentiment, I do have a preference for my bread-and-butter games. And for me these do not lie in the D&D-style nor the narrative-style games. They do lie in the Shadowrun/Hârnmaster/etc style of slightly more complex rulesets.
For me, one of the big weaknesses of a system like traditional mechanics is the real-world speed at which it resolves and the focus on the sidecar physics mechanics.
Yes but even in PbtA you're probably not going to reach real world speeds, even if you play it fast. And you're right that if you go into the sim side, you pick very carefully what to model and what to abstract away. Compromises need to be made in any case, no matter the system.
And round-robin style attacks, to return to the topic, put ME into a world of Xs and Os. It's boardgame-like.
Oh I get that. My problem with this idea is that between turn-based action and the weird fuzziness that comes with HP....
The third part of my comparing movie fights with combat rules in RPGs will focus on how damage works in movies.

I'm checking in these threads here if my logic regarding my observations is sound and I'm looking if anyone has suggestions for better/easier/faster/simpler/more accurately capturing the spirit of cinematic combat than the game rules I have come in my own RPG system (no, it's decidedly not a D&D off-shot, unless we consider all RPGs D&D offs-shoots).