A coupla points:
"But in real life how stupid are you if you run around sprinting an ram your gun into a wall????
How often have you every watched a military tape/video/movie an seen someone stumbling into a wall with a gun??? lol
answer......YOU DON'T!!!!!"
IRL, particularly when working in an urban or CQB setting, you bang all your **** into lots of stuff, including your weapon. If you're lucky enough to not be wearing some kinda pack then things are a bit easier, but if you are then it's not uncommon for a fella to actually get stuck momentarily in a doorframe.
"How far exactly can you pull a weapon back if it's at your shoulder?"
Actually, for retention purposes, you tend to let the butt slip under your arm and in this position you can bring it back pretty fecking far and still get good hits fairly easily to 10-15m. Occasionally, you may tilt the weapon sideways and slide it up on top of your shoulder. If using red dot optics and a light round such as 5.56 or 7.62x39, then it's pretty easy to be accurate here as well.
I think the weapon collision thing is cool, but to implement it properly there should be a toggle to allow you to go to a position commonly known as sul (meaning south), where your weapon is held sideways close to the body with the barrel pointed directly at the ground just in front of one's toes. This would effectively remove the weapon collision box to allow one to slip into tight spaces or peek around corners without poking the gun out for all to see.