For anyone who hasn't seen this video comparing sway between SS and Insurgency.
I think the biggest difference in feel between SS and Insurgency is the new sway mechanic. The sway while fatigued or suppressed is far greater in SS and makes aiming far too difficult.
There's two main reasons why I think the system should be reverted back/changed to more closely resemble the last game:
The TTK in SS is greater than in Insurgency, which means that shots should be easier to land to compensate. Insurgency, with its lower sway, allowed you to land more shots effectively even with 1-2 hit kills. With Sandstorm, it feels you are spraying while the gun sways/recoils everywhere while trying to land the 3-shots needed to kill someone.
SS is coming to consoles, and joysticks are far more difficult to use to aim precisely. The sway system in SS isn't necessarily terrible, but console players will definitely have a harder time landing shots effectively. Use any section of the above clip of sway in Sandstorm and imagine trying to compensate against that on console...
I've noticed that SS has also introduced a mechanic where sway can be completely eliminated by certain weapon/scope/stance combinations even without a bipod.
Ex. M16A2 with 3x scope, crouched, hold-breath.
M4A1 with red dot, prone, hold-breath.
Any sniper with 4x scope, prone, no hold-breath.
While this may be to compensate against the increased general sway, I feel this mechanic is kind of useless. For one, it makes spending points on a bipod almost redundant, especially with sniper rifles. And it makes the meta of crouching/standing still while holding breath too heavily relied-on. It de-incentivizes pushing hard since defenders can crouch or prone and have absolutely no sway while shooting attackers.
Insurgency had some trace amounts of sway even when prone and holding breath, and was impossible to get rid of sway entirely unless using a bipod. That system makes even more sense for SS over Insurgency given the new TTK and movement systems.