Aiming the console is not hard (if you live at least 1 story high, else go to a friend's house).
What you do is open the largest window, take a breath, pull the console back like they do in the Olympics with stones, ready, aim, do a 360 and then noscope that [censored] out the window.
While doing this, scream '[censored] you Microsoft and your [censored] thumb-stick aiming you ruined games forever' (even if it's a Sony console).
Then you go back to your room and touch your gaming mouse softly, whispering that you will never be with another peripheral in your life.

But to remain consistent and get better having the same sensitivity is a must. Otherwise you wouldn't see professionals be so keen on playing at certain sensitivities.

And promptly cheat on it the moment you touch your keyboard...

Agreed with almost everything in OP, although I don't have high hopes. Additionally, it's very possible that hits will be partially based on skill/perk/whatever in game level like it was in Skyrim.

I wonder, would it be possible to mod such a behavior?

Eh, well, might just be the difference in how we modded our games.

I don't have an issue with any of the OPs requests (tho he seems a bit overly-picky about some of the issues), but why would you ask for a myriad of options and then have THIS:

• don't have different X / Y sensitivity

I get that having those different can cause mousing issues, but if someone wants to set those differently, wouldn't an option to do so (even if in a settings file) be perferable to not allowing any changes at all? Certainly the default should be equivalent sensitivity, but requesting that an option NOT be available goes against the basis for all your other requests.

You mean that impact of stats on projectiles isn't only spread (and damage for some unfathomable Bethesda logic), but also whether it hits or not and/or autoaim? It was modded out in Skyrim (can't find the mod on Nexus).

Pretty sure OP meant different as in hard set X/Y ratio other than 1:1, not that you can set each separately, which would of course be great.

No no I mean go in the code, remove the hardcoded zoom sensitivity drop, remove the different x/y sensitivity, remove the mouse acceleration and then

just publish the mod to nexus / steam workshop calling it 'Actually decent mouse aim mod'

I hope that they do that for all types of controllers including mouse! You can also attach a controller into a pc but for desk-gamers, a mouse and keyboard fits better.

The reason I choose pc is the ease of steam, and using mouse and kb. I cannot aim with a controller because shooters were not made for a controller. But people prefer it cause they're casual.

The majority of people don't even have a desk to speak of, they prefer just plugging a console in, not worrying about compatibility, drivers, just plug the game and it runs.

On pc you have to worry about so many things. Look how Batman ran with 2 1000$ gpus ... 25 fps. So why get a controller to play pc shooters? Why not just pay 350$ and get a console?