I'm going to assume that your particular berserk button is when people say that RPG mechanics are outdated simply because they used to substitute for what engine limitations couldn't handle, if you get what I mean. No offense intended, just a guess.
It comes of an ignorance about the technology... You see this when someone asserts ~for instance about Fallout, that they had to make them [isometric] that way, because they couldn't make first person games back then. [

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People also commonly don't understand what they see of it (perhaps for lack of familiarity). Someone once said to me, "That computer is old; it doesn't even have Google on it.". Another person was stunned [incredulous] at the graphics quality of a 1984 arcade game ~because they did not understand the technology of what they were seeing. [That game was
Cobra Command BTW; here is a 90's
console port of it.]
Fallout was isometric [most likely] for an easy reason:
The fact is that most of core FO3's gameplay could have been managed with the same tech that was available the year Fallout shipped.... if that's all the game was intended to be.

We could have been stuck with something like this instead:
Mainstream gamers don't like numbers and RNGs speaking for what their hands and reflexes can do, so that's why it's a common criticism for old-school games.
Hell, people unfamiliar with such mechanics got pissed with the new X-COM because you could miss even with a 90% hit chance (which is actually correct). Maybe it's fair to say this is what Fallout is, but I don't think it would be wise to suggest every single RPG should have numbers speak for the player's ability.After all, casual gamers see player characters in RPGs as an extension of themselves, even when doing things that don't always match their personality.
Their reflexes should have exactly ~squat to do with anything ~in an RPG; it is their character's reflexes that should matter. This is the reason for a character sheet. The purpose of PC stats and skills is to indicate when to say "NO". RNG is the absolute best option [period] for deciding an impartial outcome. It indicates ~life and circumstance; it enforces the reality of having only a measure of control in situations; and sometimes less than one likes.
Mainstream gamers and even mainstream designers are not wanting RPGs; they want empowerment fantasy. RPGs can offer that, but not the servile typical examples [calling themselves RPGs] that we get these days; one that never say 'no' to the player ~only "not yet". Sometimes a PC is supposed to fail. That's what it means for that PC to be in that situation. The same exceptional skill that allows them to succeed in places where most would fail, leaves weaknesses in their abilities elsewhere. The silver tongued 20 year old conman is not also the hardened combat veteran with unbreakable cool; and not also the PHD medical doctor; and not also the near preternatural pickpocket; and not also experienced mechanical engineer.
When the pickpocket and/or conman face down a squad of heavily armed & armored opponents, it is not in their character to start landing headshots while edging towards cover, and preparing a grenade. It's not, because they can't be all that they are, and have spent their lives fighting as a mercenary or in special forces [instead]. Yet that is exactly what these players expect when they demand that the game let them get away with handling the fight personally... cool-headedly making shots that their character is often simply incapable of.
*This goes both ways too... The reverse is to roleplay the war hero veteran sniper ~who cannot shoot straight while under the player's control. In Witcher 2&3 Geralt is an absolute loon in a fight ~unless the player can control their [puppet witcher] comparably to the character's expected level of expertise; as a veteran professional monster hunter. One cannot get the experience of roleplaying Geralt, or Bruce Lee, or Conan... if the character is hamstrung by their control of them. Roleplaying Bruce Lee or Chuck Norris [characters] should deliver on their expertise and behavior, just the same as roleplaying Sheldon from 'The Big Bang Theory; and how would Sheldon fair in a back alley knife fight instead of Lee or Norris?
Not everyone wants to play a vulnerable or flawed character in games. Not everyone wants a challenge. Do you see that as wrong?
I see it as picking the wrong genre; (and that goes for players and developers alike).
As to the perspective [being the problem for FO3], FPP generally encourages player substitution for the PC; so it's no longer the PC in situ ~it's the player. Many players become annoyed when their PC's limitations are enforced [upon them
personally]. Eventually we get games [so called RPGs] that simply do not enforce the limitations of the PC; the PC becomes a vestigial inconvenience whose abilities only serve as enablers. In the end we are left with little to no RPG aspects at all, and a whole lot of ego-shooter in it's place.