Moot, did DICE ever fix the mouse acceleration on the PC version?
Everything else never fixed, or fixed then rebroken (sometimes multiple times EG MG36 dot sight):
Input delay on basic things like movement: you must wait between inputs when commanding a string of inputs, e.g. fire, run, crouch, run, fire, etc. Pressing them too quick means they're ignored. Gameplay design choice? Then why not only delay action? Nonsense anyway you look at it.
Some actions also delayed for no apparent reason. E.G. C4 trigger
You can't pick what you're interacting with. Completely unpredictable behavior in critical game event, EG picking up kits instead of defusing MCOM. Never fixed, never even mentionned as an issue.
Tactical game breaker: you'll sound off (e.g. passing out a med kit or throwing grenade) without knowing about it. You give away location without even knowing about it. Never fixed.
Bad hit box nextcode, then "fixed" with even worse system (they made hitbox bigger, literally).
Treadmill effect, and sometimes you get stuck on nothing EG move up against top of stairs while crouched. Same absurd effects with soft trees and bushes- somehow a soldier couldn't push thru such things.
Bad collision boxes: you'll hit objects inches away from their edge.
Reticles are crap. Neither quality nor customization whatsoever on one of the bread & butter elements of the game. This (letting players choose their ergonomics) is industry standard since what.... Quake 1?
A few gunsights don't point straight. EG SAW, M416. Never fixed
Mounted guns don't line up with camera when swiveled. You don't know where it'll shoot. Never fixed either.
Event/server text flashes in your face, right in focal point above ironsights, regardless your resolution. All they have to do is make text top-justified. Another bonehead/slacker mistake. What excuse do they have for this kinda thing when they're making millions and millions in profits?
No server info from within server
Can't quit server without waiting for respawn timer
Can't join another server (e.g. where your friends are) without quitting
Only 20 friends allowed
There's probably more but that's a good chunk of the actual inarguable flaws, leaving out dubious design choices. Overall just ridiculous. BF3 ought to be more of the same: great content mired in absurd flaws that no studio making 100M$+ on one game has excuses for.