Combat in a game with no randomness is simply a puzzle with one solution. Its zork-- its an adventure game. There would be no point to having combat or levels or stats. You either do, or you don't. It would be tedious with no replayability, no tension, and no strategy beyond finding a way to make your number be high enough to win. I guess you could make a more complicated deterministic model like chess, but chess is boring and sucks.
Chess is a game that is still being played more than 1'000 years after its inception, and it currently has 100s of millions of fans. So we will have to disagree on that.
Also, what you are describing is not how chess, its variants, and other chess-like games necessarily work. There does not have to be a single solution. It is possible that there is theoretically an optimal solution (as far as proper chess is concerned, we don't know yet), but that optimal solution does not have to be the same one in all playthroughs. There is randomness and choice in chess/chess-like games too, just of a different nature (e.g. initial conditions).
I think some of this desire is stemming from their feelings being hurt when they lose.
Exactly the opposite. When you lose in deterministic games, you have noone to blame but yourself.
You are agreeing with me on the second point. I said my brother and his friends whine about RNG's sometimes in order to explain a failure.
Because of these 'unreserved losses' they have come to believe a game without RNG would be better, because then they would not have lost...... because of course the only reason they lost was due to the RNG cheating or perhaps having a 'bug'.
About chess, yes its popular, so is McDonalds and monopoly. The reason why chess would suck as an RPG combat system (IMO) is because the pieces (characters) are bland and static. I believe a deterministic system would also suffer from a lack of distinction as well as simplistic and generic tactics and abilities .
It really does depend on the game in question and the method of random used. There's no one-size-fits-all answer to whether RNG improves or harms a game's combat and other systems.
I've played strategy games where the RNG is utterly stupid and does indeed ruin the whole point of strategy and, worse than that, ruin the whole concept of varied tactics, not to mention feel like cheating:
Because it's implementation of RNG was absurd. In a strategy game, knowing how many units of what type you require to perform their job is pretty much crucial to the whole point of the game. If the game then fucks you over with absurdity and then says "ah well, that's life, it happened once vaguely in history... if you stretch the idea like a rubber band", then, I'm sorry, but the obvious reaction is "oh, fuck off game".
When RPGs moved towards their modern status of AAA action adventure type jobbies, RNG was no longer needed as much because every other stat-based element was being removed anyway, and the way to substitute the RNG of to-hit is to... bloat HP... so you still have to strike the enemy the same number of times as you would in an RNG system, you just get the 'action' of hitting every time. When people complain of HP bloat in RPGs, they are often unaware it goes hand-in-hand with playing a game that has either a shoddy RNG system or one with no RNG:
Everything now has health
bars instead of HP
numbers. And your job is to watch these bars slowly dwindle to nothing, not too dissimilar the loading screen bars slowly filling up between said encounters. The most random systems like this can do is to guarantee a hit, but vary the value of that hit between a minimum and a maximum.
This last version of RNG, a compromise where you always hit but have varied values of hit, is probably the best compromise if one was determined to banish to-hit RNG and I've seen it work in some games I've thoroughly enjoyed:
In the above game the numbers are retained by increasing the number of units-in-the-stack rather than one specific character's health bar increasing exponentially through levelling. The game retains the drama of RNG values because depleting an opposition stack is crucial to you not losing too many units, while still giving the pleasure of always hitting*, still providing the intelligence of strategy and tactics, and still being turn-based. *Even this game did have to-hit RNG, it was possible to miss, it was just very rare and relied on very specific scenarios.
Why cRPGs benefit so greatly from RNG systems relating to to-hit stats is primarily because cRPGs are about individual adventurers usually facing individual opponents. And by individuals that can mean lots of individuals on the screen, of course. Now let's imagine 4 player characters vs 4 AI enemies. They all are level 2 and they all have 20 hit points and one hit from a sword does 6-10 damage. In this scenario it doesn't matter what you do, at least one of your team is going to die, unless you can fathom some kind of drastic cheese or the AI has an exploitable flaw. And worse than that, someone's going to die really quickly. More importantly than that, however, it means that all your team members have the same values, and the enemies have the same values as your team... so... how do you implement variety of build?
Do you make wizards cast fireballs that hit for 6-10 instead of make them have swords? Archers that have arrows that hit for 6-10 instead of magic or swords? Do you just have tuns of different things all doing 6-10 guaranteed damage? You could, but what would be the point other than aesthetics? Your game wouldn't change in any significant way from the first moment to the last, no matter what you did.
Ok, so that's tedious, so how about we make the wizard's fireball give 10-15 damage instead, because fireballs are exciting and fun! You could do, but then why not make all your team a team of wizards, why would you ever pick anything else to have in your party? You'd have to invent some kind of downside to the obvious over-powerment. Without the RNG, you'd have to slow down the cooldown, or make it slower to fire than a sword, or in some way limit their use. Oh dear, you'd have to balance this so precisely that the end result would be no different to everyone just hitting at 6-10 every round.
By going down the road of removing to-hit RNG, you are inevitably led to a path of: "levelling a character = substantially more HP (AKA bloat), much greater difficulty/preciseness required to balance the game, to which that balance will automatically deliver mostly boring encounters, shafted character diversity, weaker itemisation, harder to implement original itemisation, etc etc etc.
By having a to-hit RNG before one even considers damage RNG in a cRPG allows for much looser encounter design, and therefore much more fun and varied encounter design, greater variety of character builds who all offer different strengths and weaknesses and a greatly reduced reliance on HP, allowing all the characters in the universe, both ours and theirs, to provide much more abstract realism.
So for strategy games, layers of RNG can kill the whole point of the game, but for cRPGs, the more layers you have, as long as they are not absurd, the more you can breathe life into it.