As for the whole Venom Snake thing. I had hoped that it was not the case that you weren't actually a double, even though, let's be honest it was pretty obvious, if not from the trailers, then from the heavy handed opening where you give a name and create an avatar. Who you were was by process of elimination the medic, so I wasn't shocked by that. I did however find myself OK with the twist though. Venom doesn't act like the Big Boss we knew, something that is abundantly clear when you go through episode 46. I also find myself LIKING Venom a whole lot. He's not motivated by vengeance, or at least not entirely, but a lot of his motivation is guilt. He wasn't able to save Miller and Boss due to not finding the second Bomb in Paz. He's clearly not consciously aware of it, but it shows through in his actions. He WANTS to save people, Quiet, the kids, even Huey gets spared.
I found the stuff with Paz might be the most important character beat for him in the game. He rewrote his whole memory of events into making the right call and saving her. It's just ironic that he didn't know that no matter what, she was going to die, they had removed far too many internal organs, she had hours left according to the tapes. But that explosion nearly killed Boss, killed Chico, and crippled him. And he has to walk around with bits of Paz in him at all times. Kinda fucked when you think about it. The stuff also implies that medic might have had a thing for her, but that could just be me.