That final complaint is self-inflicted. Why not play the game in the manner it was intended?
I think the hardcore mode merely aggravated what were pre-existing problems with the game.
Moving john around areas that are flat and open generally works well, but anytime there's stuff around he moves like garbage, constantly banging into things and stopping suddenly. It's hard to get him to go up steps/ledges if he isn't facing them directly. In many cases, locations that looked like cover ended up not providing cover, meaning you take cover only to die anyway, or not being cover-objects at all, resulting in john sliding over and taking cover behind some other object nearby, often placing him directly in line of fire.
I turned the aim sensitivity to the max and still struggled with aiming whenever enemies got within 20 feet or so, which happened a lot. the game devolved into a challenge to keep enemies at distance, especially the missions where waves of mounted enemies came at you while you were traveling somewhere because a single enemy at close range was almost certain to kill me before i could even target him unless I used dead-eye. I also died a whole lot early in the game to roving blue-dot bandits because i would just be riding along, see a blue dot and go to investigate, it wouldn't show that they were enemies until i got close, and then suddenly they'd open fire and i would die. I eventually learned how to recognize the different blue-dot scenes from a distance. Still, any encounter while mounted was an invitation to die.
Also the knife combat was infuriating in those instances where it was necessary. Sometimes I could get it to sneak-kill guys, sometimes marston would just stand there crouching and looking stupid and the camera would turn oddly and then I'd die, all while I madly tried to swing the knife.
I would also note that I mention these things mostly as constructive criticism that I would hope they work on for the next game. I certainly got my money's worth, and the game does a lot of things I really liked. It just very much felt like a "first try." And while I mentioned that I played it on hardcore just to be clear, my girlfriend played it on normal and died a lot from the same problems, though she just quit playing after a few hours in frustration. Much of the time, hardcore mode meant I needed to be really careful, which I was cool with and wanted, but it also lead to a lot of really cheap deaths when the game forced me into certain set-pieces where being careful wasn't really an option.