I think a lot of how you play the game comes down to whether you're playing it on a Mouse/Keyboard or a controller.None of that matches my experience, and I found it more viable to rely on my agility. Armored enemies can be taken down pretty easily from the back, they have a slow turn radius which can be exploited. The robotic ones have batteries there to be shot off.
I was watching a TwitchTV streamer play the PC version with 360 controller the other day, then after the chat bitched him out and shamed him enough, he switched to M/K and was playing the game very differently. Less cover, less ADS, and less spray n pray.
Between run n gun, cover, and stealth, it's to the game's compliment that all three different styles are viable and enjoyable (in my opinion).