Fight, props to you man for trying to learn from it rather than saying the player is a "hack". I watched about 5 mins of the video and there was really only one thing I found slightly suspect. When the player got on the 50 cal, it didn't seem like a burst fire and was having really good accuracy. I don't get on that 50 that much, but the times I have I haven't seemed to have that kind of luck.
However, I know for a fact this player isn't hacking when I see how he fired the mid. He missed. He missed several times.
So if this player is good, I always try to pick up gameplay pointer from them. See what they are doing different. Because I may think I know how best to use a weapon, then someone owns me with the same weapon or they use a weapon in a very efficient manner that I think is crap.
Did you see how the player used the deagle (a gun I think is crap despite it's great stats)? Rather than staying aimed in the entire time, he brought the gun down slightly between each shot when he was shooting down on the stairs in the crows nest on c flag. He had GREAT accuracy. Accuracy I haven't experienced with that gun. Maybe he's onto something with the way the game calculates the accuracy of the deagle. Or maybe he taught that to himself because the accuracy resets in that short amount of time. Or maybe im just crazy? Probably. However, it something I am going to try.
Also, this player moves in a way I see pro players tend to... reserved. Pro players tend to fire and retreat. They let you come to them. They usually don't go in guns blazing. They fire from a decently protected position for a bit and then retreat because the accuracy goes to pot.
Many on here know the Woozy's on metro. They are pretty good players. I have spec'd both trouble and crazy. Looked and their loadout's. See what they do. If they are hacking, they are doing a good job hiding it by either know when someone is specin them or turning it on and off. They move like pros, they are reserved as well. However, I did pick up a couple things from their gun loadouts. I always used to be a fan of the heavy barrel attachment no matter what gun. I figured I could hold the gun steady on my own until I saw what both of those guys used. They like to use the muzzle break. So I tried the muzzle break out. More of my shots seemed to consistently hit more with that over the heavy barrel? Doesn't make sense since the accuracy is supposed to go down. I don't know but it worked better for me.