With how fast stamina drains and how SLOW it regenerates, having it at 100% is almost never an option unless you're sitting on a flag defending. Even if you sprint for 20 meters, and you have 70-80% stamina, the debuff is severe enough to put you at a pretty noticeable disadvantage.
The way I see it there's 3 solutions, either decrease the sway debuff for 50% stamina (something logarithmic like having a slowly increasing debuff up until 50%, and then the debuff scales up much more quickly past that point). This is similar to the old stamina system which in my opinion was much better than the current one.
OR, decrease the rate at which stamina drains (100% stamina drain in 150m or 200m instead of 100m)
OR just increase the rate at which stamina regenerates.
In case of any of these solutions, you will still be punished for being out of position, any enemy who's positioned better and already has his scope up will be more likely to kill you, but at least you feel much less helpless.
Any of these solutions will preserve the core gameplay loop and mechanics, preserve the emphasis on teamwork and positioning, and make the game more FUN. You'll have a bit more ability to push up and turtling will be a little less rewarding.