Mind you I think Rising's main plot is better written than MGSV's ultimate plot at least in that you can work out purely based on the mandatory cutscenes what is going on, unlike MGSV where I had no fucking clue what Skull Face's actual plot or allegiances were until Ocelot laborously explained the plot on cassettes. Admittedly this is because the final boss just monologues his plan at you, but still.
Well i expressed my hatred for audiologs many times in the past (i find them a very lazy narrative device, and almost no one does them well) so i feel you when you say crucial stuff is relegated to them.
Personally i don't think MGSV's plot is total shit like some, i think it has the right ingredients, put together in the wrong manner.
And i don't even mind big plot holes too much (such as why can't Quiet write down shit in English? Why can't people just not speak Kikongo until a cure is found? etc) otherwise i wouldn't be able to appreciate ANY MGS, since they're all full of implausibilities and plot holes.
The biggest betrayals of expectations I had, were:
1) Pacing.
2) Tone.
The pace is completely fucked for reason explained multiple times in the thread, where in Chapter 1 nothing happens for about 40 hours, and as soon as you get to Chapter 2, shit gets rushed into a wonky, half assed finale.
With most of the crucial shit happening on tape, the material to work with was, potentially, there.
The tone hinted before release, was to be something very dark, violent, and shocking, all this masturbation about taboo themes, "i'm gonna get kicked out of the industry" and all that bullshit.
And then the game is more tame than other entries int he series, Venom Snake never does anything particularly bad (shooting his men in mother base wasn't even an act of selfishness or anything) he doesn't even kill one of the shittiest guys in the game (Huey).
You go watch the Nuclear trailer, and you expect him to burn villages with white napalm or some shit, and in the end the most controversial shit it has, is a lady's bikini.
Finally, and this is related to tone, the twist itself, i thought, was a very interesting idea handled stupidly.
First of all, it doesn't really have that big an implication, because Venom Boss didn't really get to interact and influence anyone outside of Liquid and, MAYBE Miller (biggest implication would be how much of a dickhead OG Big Boss is, right from the start).
Second of all, and most importantly, they decided to go with this "meta commentary" horseshit ("YOU are the boss!") that takes away any chance at having an actually interesting character, bringing something to the story.
What they could've done is have a person forced into the role of Big Boss, but with a different personality, show off his struggle in reconciling these two aspects of his psyche: One telling him he HAS to desire a world of constant perpetual war (Big Boss' dream and mental inception) and his own personality, maybe dreaming of something else.
Show off this struggle throughout the game and have Ocelot try to drag him on BB's side, while Miller pulls him to the other.
Then show him giving in and sacrificing, when BB finally decides to have him killed as a pawn in his master plan (by guiding Solid Snake to get rid of him).
You could've had this, and instead they went with the "Venom Snake is a silent puppet you inhabit" and he says jack shit for 70 hours of game, and he sits silent, emotionless and without even flinching once, in a 40 minutes car ride with SkullFace, the man who destroyed and put him in a 9 years coma, telling him is master plan.
And this applies in many other cases for this game, the elements of a good, interesting story are there, they're just handled like shit.