Man I got spoiled on the twist with the double but I don't think I would've been thrilled with it as a surprise...
I mean it's a cool idea, it would work, but the execution... I mean did Paz ever come back like in the 'coming soon' cutscene? The whole of act two feels unfinished, there were fantastic things in it, like the quarantine, but it never really wraps up. You have volgin in captivity, nothing. Quiet's sacrifice is sorta unsatisfying since they never explained why she didn't just write things, plus losing your GMP and time investment is like a kick in the balls. And the third boy and Eli have a fucking metal gear and thats just left to hang around. Not to mention that it is never stated what triggered Venom's regaining of memory.
Maybe they'll tack on a new set of missions. Maybe I'm sad it's over, or 84 hours playtime in a week has put too much metal gear on my brain, but I just feel a little sour right now.