According to training at the start of Operation Flashpoint - Cold War Crisis: "A soldier must be fast, exact and effective with his weapon..."
I don't think the current relationship between going from 'freelook' to 'optics' allows for this.
My suggestion is that, when using 'look'/'freelook' to gain situational awareness, going into 'optics' mode should automatically orient the optics (perhaps the whole character?) to where you are *looking*, and not 'straight ahead' in the direction you are going (Of course the 'centre' of where you are 'free-looking' will probably not be excatly on any spotted threat/target that prompted going into optics mode, so you'd still have to aim properly).
I think having this relationship between looking around and using optics (at least as an option) would beter simulate the very fluid "two step" process that you would undertake in real life if you elected to immidiately fire on a threat that was to the side of you (ie: 1-generally orient yourself to where you saw the threat, and 2) aim with your optics).
As ARMA (2 & 3) currently stand, you have to do these steps "one at a time" rather than simulteneously - either orient to target, and then aim, or raise optics (facing forward) and then 'hunt around' for the target - neither of these options makes for being "fast, exact and effective" IMHO...
A Blushing Crow
PS - If I've totally missed that there is already an option for 'instantly orient optics to free-look direction' then I am more than happy to be told! :-)