Changing stances uses up stamina (crouching, proning, standing up),
unable to move durning the changing of stances (meaning if im standing still and press the bind to go prone, I can only start moving when im actually prone),
unable to move mid air (When i walk forward and jump, i will jump forward and cant go left/right during the jump, if i hold D and jump i will jump to the right and cant move forwards/backwards during the jump etc.)
Possible freefalling stance when jumping from a high distance like an airplane, things fall faster, and its easier to die from falling.
Jumping in water from 500m should still kill you
Some weapons require going prone or a bipod of maximum potential, such as high caliber and stronger snipers, and LMGs. LMGs should be very deadly when deployed but when moving an assault rifle could easily replace it.
Longer lung capacity underwater, only able to use pistols on surface of water, harder swimming based on equipment.