Absolutely. As shown by this very thread. Asisreo would prefer, as far as I can tell, to change absolutely nothing, or as little as humanly possible, about the Fighter class. And whether or not that actually is their position, many others definitely have expressed that exact view on this forum over the years. The "no! Add no flavor or extra bells and whistles! The Fighter being a blank slate and slightly less flavorful than plain oatmeal is it's greatest strength!" crowd, the ones who continually advocate against even the smallest changes and may even grumble about the existence of things like the Eldritch Knight in the first place.
Then, frankly, you haven't been paying attention to the conversations about it for the past...ooh, 15 years at least? This was a huge part of the 4e edition war, for example. All the talk about Fighters shooting lightning bolts out of inappropriate orifices and such.
Yes, people had a lot of issues with 4e, but the whole structure of that game was so different that I would be somewhat careful about extrapolating a particularly direct connection to the current conversation. In 4e a lot of mechanics were very gamey and meta, and there indeed was not much mechanical differentiation between magical and non-magical powers. Those are things I would avoid, but I don't think any of that would make much sense in 5e design paradigm anyway, so they're unlikely to come up, unless one intentionally tries to mimic 4e structures.
The thing is, yes, most folks probably would be cool with superheroic high-level fighters. But most folks aren't super upset about not having them either; martial superheroics has broad appeal, but that support is weak, few are willing to go up to bat for it. Sort of like how decriminalization of marijuana has broad support in the US, but few voters (and fewer politicians) care enough about it for or against to make it a key issue at the polls, leading to the ridiculous nebulous schism where several states are openly violating federal law but the federal government looks the other way. Except that in this case, the vocal groups mostly do oppose it and will loudly and proudly fight against it--even to the point of claiming that the silent majority supports them.
Sure. And ultimately WoTC has to assess whether any change would alienate more people than it would attract. And this is an edition that a lot of people like, so there are no huge issues. But as complaints about the edition go, the lacking usefulness of martials at higher levels is pretty common, so it would make some sense to address it some way. And I also have hard time imagining that giving fighter classes and subclasses couple of new class features past level ten would cause a mass exodus of players, especially if you generally wouldn't go wilder than low-tier supers such as Captain America.
Like consider the Champion, that is generally seen as a dud. But it is a fine concept:
"The archetypal Champion focuses on the development of raw physical power honed to deadly perfection. Those who model themselves on this archetype combine rigorous training with physical excellence to deal devastating blows."
This would be a excellent starting point to have a fighter that seeks physical perfection, and at high levels achieves superheroic athletic capabilities, allowing mimicking mythical heroes such as Heracles or Samson. And it already has features that lean into that direction, they're just underwhelming and do not really fulfil the fantasy. So just boost it an make it work!
I really, really, REALLY don't think "give the Fighter meaningful contributions outside of combat, even if they aren't necessarily flashy or major," is such a "super specific and niche desire." And I have refrained from setting narrowly specific mechanical goals, speaking instead in generalities and (paraphrasing myself) "this has the concept, but would need to be translated to 5e properly" examples, specifically in order to avoid being "super specific and niche."
Yes, that is not a niche desire, it is very reasonable and common desire. Abandoning fighter and designing a parallel mythic fighter class so that one can play the illogical concept of level one Heracles however is niche.
The Rogue is...okay. I'd prefer it had more, but it's okay. Bringing the Fighter into a similar ballpark, but not quite as major or focused, would help a lot. Tweaking them both up (e.g. bringing the Fighter up to where the Rogue is now and bringing the Rogue up a bit further) would be decent. I do not have the brain or the energy to give design examples at present. But there are paths forward that can be flavorful, open to a variety of interpretations, and not particularly complex.
Yes, I fully agree.
And honestly? A big part of the problem is that there are two opposition parties that get along just fine with one another but have mutually incompatible demands of anyone who wants change (assuming they're even willing to permit change at all). You have the (presumed) Asisreo-like group that wants the Fighter to remain pretty much exactly how it is, and will accept no changes to its features or contents, that's their line in the sand. And then we have those like you, the hyper reductionists, who are often opposed to having even as many classes as we already have let alone any new ones; their deal breaker is that nothing, zip zero nada, may be added in terms of new classes.
So...those of us who want change can't ask for the Fighter to get new features because the former group opposes any changes to the Fighter class: "go make a new class and leave my beloved Fighter alone!" And we can't ask for a new class to do the job because the latter group opposes the introduction of any new classes whatsoever: "We already have classes for that, just fix them so they do the job and leave the already over loaded archetypes alone!" At which point we must now content ourselves with no change within and no change without, the only thing that can please all opposition...by denying us literally any of the things we want. Funny how that works that way...and how people get confused at the level of emotion that arises in conversations like this.
First of, if I were 'hyper reductionist' I would advocating having only three or four classes in total. But yes, I generally oppose adding classes, especially if the archetypes desired are so close that they can easily achieved via some tweaking and subclasses as is the case here.
And I'd also point out that adding new classes and their several associated subclasses is massively more work than tweaking the existing classes. It is highly unlikely to going to happen, and advocating for it is a distraction for the actual matter of improving the martials we have. I also think that 'no chances whatsoever' brigade is not actually particularly big, and most of them would actually accept minor tweaking.