I noticed one small problem/inconvenience with the combat pace mode.
While running around without being able to fire (weapon is at your shoulder but slightly lowered) you are unable to simply bring up your weapon to fire with just pressing the left mouse button, this is especially annoying when having close range encounters while considering that in real life one is able to bring up his weapon in under one second while in game you'd have to struggle hitting either your c key to activate the combat pace with weapon up or pressing the right mouse button to enter the sights.

I would simply suggest making it possible to activate the combat pace with weapon up with simply clicking the button which is assigned for firing your weapon.(Usually the left mouse button.)