First of all, to make things clear, my definitions are:

Tapping a key = Better explained with images: https://www.youtube.com/watch?feature=player_detailpage&v=nxyrR4jI1T8#t=9s

Sprinting = Running the fastest you can (By default, holding down SHIFT).

Jog = Walking fast, whatever combat pace you have.

Quicker Run = Walking fast with your sights slightly downwards.

Aiming Run = Walking fast with your sights up.

Moving in ArmA 3's default controls don't feel very fluid right now. If you are in a tight situation and quickly need to stop Jogging, it's quite confusing to press W+S, especially if you're running diagonally; not to mention that you briefly stop moving.
Also, the fact that you have to turn ON combat pace, then afterwards turn ON running mode to make you run isn't good. (Assuming you were walking).

My suggestions to fix these issues:

make HOLDING DOWN SHIFT give you a TEMPORARY RUN;
TAPPING SHIFT make you SPRINT;
Leave combat pace as it is;
Make default running stance as walking slow;
It would work very similiarly to GTA 4 on PC, which has very good controls.