Sniper elite 4 for $6 (5 is good too, and $20) is everything I wanted MGSV to be. It's its own game so the stealth mechanics are different (sound is a major factor), and the gunplay is much more reliant on sniper rifles (though I use a silenced pistol a lot too, plus melee takedowns), but it's every bit comparable in terms of an excellent stealth engine with responsive, engaging AI. Where it shines is that unlike metal gear, which was forced out before it was populated, the mission areas are huge and jam packed with enemy action. If the ground zeroes map was a little bigger and built out into a full game, that's how Sniper Elite feels.
Also, because they can, you can snipe grenades off of enemies to explode them, and they'll chain to other environmental explosives (I haven't seen this in 5; not sure if they removed it or I just haven't noticed an enemy with a grenade on them), and the sniping is extremely satisfying with slow-motion x-rays of the body parts hit (also can be turned off) and good physics based on bullet drop, wind, velocity, etc.