I didn't say MGSV was trash. I said the twist was. Besides, MGS3 has a great story about how soldiers are played against each-other as political pawns. And Peace Walker has a fairly trash story about nuclear deterrence and the moral ambiguity in owning a nuke for that purpose.
Maybe you don't know about Big Boss in MG2. He was attempting to engulf the world in a state of perpetual warfare, where the orphans of the last war are the soldiers of the next. He's as much of a villain as any character could aspire to be. He was far from the jilted dude he is in Peace Walker.
There isn't a clear path as to why the dude from Peace Walker, a hired gun, becomes the dude from MG2, a tyrant with a war fetish.
Also, you're missing my point with the memories angle. It would have made MGS3 and Peace Walker more important, because that's all Big Boss would know about himself - that's all anyone else could tell him. He'd be a dude in that role without the context of having lived a life. He'd be Big Boss if he didn't have memories of a non-war childhood, or that of non-war interactions. It would be Big Boss, not Jack. That dude wanting perpetual war makes sense, because he'd know nothing else.
MGS3 and Peace Walker were written with the intention of bringing Big Boss in line with his previously established character and not continuing further, if they failed to do that they failed in regards to the larger story.
I am familiar with how Big Boss was in MG2:SS. He was the head of a rogue nation he had built up into the world's only nuculear superpower and viewed a life of war as his only reason for himself and his fellow soldiers to exist.
The story of MGS3 was written with this in mind, the Boss is used as a political tool and has to die as a shameful traitor in order to make things right. A noble sacrifice but one that puts Jack at odds with the Pentagon and was set up so he'd set up Outer Heaven and Zanzibar Land for soldiers to have thier place. If they had never made another game in the series him doing his later actions would make sense because of what he saw and what he went through.
Similarly Peace Walker had him basically set up his proto Outer Heaven, put him at odds with Zero as the later stories had retroactively made that part of the reason for his uprisings. During the course of the story through her AI system in Peace Walker, the Boss once again sacrifices in order to make things right and prevent a nuculear holocaust. Boss views this as her rejecting him and the life of a soldier. He gets a nuke and child soldiers as part of his story and he gives a speech at the end of the game mirroring his lines in MG2:SS about how they are soldiers with no other place and continuing to fight is the reason they exist. In the Final line of the game Boss literally refers to MB as thief Outer Heaven while he finishes this speech and the game's logo turns blood red.
At this point he is not some "jilted dude" and he's not some guy who will eventually turn into a villian, he is Big Boss. Even Big Boss himself isn't the worst person there is. Grey Fox and Schneider, the guy who lead the resistance against him in MG, talk about how great of a guy he is, rescuing them and in Schneider's case how he saved refugees from Outer Heaven from NATO (iirc) bombing them to death.
This is why focusing on Boss wasn't nessesary. This is why deleting his memories makes no sense. Having him lose his memories after the explosion and only know his place by the expectation of others for him to live up to begin Big Boss might as well just make him a different character entirely. Oh wait, why does that idea sound so familiar?
