The world design lends itself to the missions but I think it's the free roam where it shines. The objective nature of missions can maybe sometimes result in sort of min-maxing of your approach: it's common to read or see on video sites how many people use silenced sniper rifles, end up using the same approach to X target, etc. In free roam there when you've tackling more random side ops or even just genuine free roam troops, sort of lends itself to just approaching however you want.
Where I always find myself coming back to are certain areas like Da Whalia, where I'll regularly come in,
scout a bit or bit and start sniping... same for
that first town. and in general just flow with the random enemies. Maybe call in a heli. Maybe infiltrate through the city from the start with just a silencer pistol and flashlight at night. Maybe set a trap to lure enemies away and ambush them from a different angle. I always like
watching air support come in at night or
through night vision a la Blackhawk Down or
Peqoud lets loose "rocket salvo rocket salvo" on a vehicle (or
some guy clearly already dead lol). Just in general raiding various outposts...
the plantation in Angola is another favorite of mine -- awesome little details to it.
All of which are often creative and sort of 'motivated' actions that basically begin with core gameplay that is fun and makes you want to try those sort of things to begin with. A general tacticle response and smoothness of inputs where things just feel smooth right, and execute like you expect them to Things like
weapon steals to dual holds-ups, or
takedowns from the ground, or
how the game transitions from third person stalking, crouching, crawling, then first person, or just
the reliability of its hit detection -- everything just responds and animates in a fluid and satisfying way.
That said, I'm rather fond of Snake Eater, Peace Walker and Militaires Sans Frontieres, and Mother Base and Diamond Dogs. So, combine that with that sort of ARMA, Delta Force, Ghost Recon world design, and satisfying creative freedom and gameplay response, and I mostly just need a landscape to scout and infiltrate within to be satisfied -- akin to replaying the same ARMA, Delta Force or Ghost Recon map over and over again in different ways.
I've likely raided my favorite few outposts in Afghanistan and Angola over a couple dozen times, and though the content is not new, the experience always feels a little bit different just based on the weapons, time of day, enemy ranks, my approach, and so forth. That's sort of brings me back every week. I can create a theme or idea, customize weapons in a new way, design a new loadout I've never tried, and then take it out on the battlefield. It's not a world sandbox per se since it's still mostly static and respawning, but it's a sort of gameplay sandbox in terms of player creativity. For all its world design or gameplay control, what really gives fuel to those things is freedom and creativity the game tools give you.
The real strength of the game is how accurately the game manifests the player's inputs: whether it's your physical ideas and inputs, or your tactical ideas and your creative ideas. Every input of your d-pad to attack an enemy or hop through a window, to try some weird idea to lure ideas, or creatively theme your loadout -- for any weakness the game has in its parts, as a sum it always seem to manifest your actions, ideas, or creativity with an accuracy and satisfaction that few games can match.
