I like this game because it is not Battlefield. Yet, every patch, it becomes and feels more like battlefield. It's time to get crazy, and bring in a new mechanic, a new feel to FPS games that no one has done, yet. Base ADS time on weapon weight, and that same weight should modify recoil.
When no action is being taken, your weapon is being held across your chest (slung).
Clicking right click brings your weapon to "hip fire" mode. (Or holding right click).
In the real world, you're using the weapon sling to hold the weight of your weapon at hip level, aka "hip fire".
Holding shift (currently hold breath) is when you ADS and starts your "timer".
After time, modified by the weapon you are holding, your weapon starts to shake and ultimately drops back to "hip fire" as you do not have the strength to continue (ADS) to hold it up on it's own.
Recoil should be focused on holding the weapon steady, not bringing a weapon back down vertically.
Unless you're firing a pistol/SMG, the weight of the weapon is enough itself to keep recoil manageable. Firing my M4, the weight of that 13 lb weapon was enough where all I had to do, was keep it in the pocket to limit bullet "spray" from the weapon shake.
Bullet spray happens naturally when the weapon shakes. When you hold a weapon tight in your pocket, you're controlling the weapon shake (aka bullet spray), the weight of the weapon itself keeps it from climbing vertically.
The AR/MGs should have virtually no vertical recoil because the weight of the weapon is MORE than enough that you do not need to "pull the weapon down".
All rifles should have minimal recoil.
SMGs and lighter should have NOTICEABLE vertical recoil, modified by weapon caliber.
Thus, when you're holding your weapon tight in your pocket, you're just compensating left and right.
(This point is more of a pet peeve) Do NOT just throw bullet spray into the game without an "explanation". When full auto firing from an UNsupported position you WILL get bullet spray, but have the weapon visually shake or something. There are sooooo many plebs that think bullet spray is a 100% natural occurrence when your weapon is 100% stabilized...
I would agree it would be acceptable to keep the "mouse down" mechanic in the game if it simulated holding the weapon tight in the pocket to mitigate the weapon shaking (bullet spray).
There should be a point to where if you mouse down too much you over come recoil and "drop" your weapon.
Every weapon should have it's own "mouse down" force to master.
If you do not mouse down enough, again the weapon does NOT kick up, it simply sprays more left - right.
Now, how this would balance out.
In burst moments, AR/MGs will be able to compete with rifles
For example, if you're running through town, and you see someone, you will have maybe 1 - 2 seconds to actually, accurately, return fire
Anything after the "initial contact" rifles will win out because AR/MGs cannot hold their sights up for accurate fire.
In CQB, the lighter weapons will have an advantage, as they should, because you can ADS a lot longer. Depending on the weapon, such as an M-TAR, you should be able to ADS for 5+ minutes at a time without an issue.
This translates to faster "clear times". The heavier the weapon will need to take more stops to recharge their ADS time every time they have a new room to clear.
Everything will stay the same for distance combat (supported positions).
IF anything would change, the only thing would be you have to "mouse down" just as much with an AR/MG when prone because you still have to compensate for weapon shake.
What would "change", realistically?
You will have to make choices on when to ADS
You will have to make more serious choices on weapons you pick due to
Map (CQB/Long range)
Play style, are you constantly assaulting "run and gun", or are you defending a position/point/FOB
Only have vertical recoil if you are using a light weapon
You will have to mouse down just as much prone with a weapon, as standing, because the weapon shakes just as hard no matter your position.
Your position modifies your ADS "time".
Kneeling adds ADS "time".
Bi-pods and supported positions all gain unlimited ADS time. (Still kind of how it is now...)
Still mouse down
That simulates holding the weapon tight in the pocket to mitigate weapon shake
If you're full auto firing when you raise your mouse up, your weapon will follow your mouse
Rifles/Small Arms will still be dominate in CQB
AR/MGs will at least have a chance now, only for one second or two, but at least a chance, when running to new positions.
All weapons will have unlimited ADS time when you are prone supported, like it is now.