Simple explanation.
You are standing weapon idle/resting.
You would expect CTRL+W or CTRL+S to transition you into standing high/low weapon ready.
That is it.
At present you need to either double tap control, or transition to crouch and then stance adjust back up. It feels a bit odd, but there would be plenty of times when you are walking where it would feel a bit more natural to go from walking idle, to peeking up higher over a wall or something of that sort with the existing stance adjusts, even if it does bring your weapon to active.
Same with walking and ducking down a bit and going to weapon ready, or combat jog. Reaction to contact or just wanting to get a way a bit faster at a ready, vs jumbling though even more keysteps from ones that already exist.