Hmm question everything could also refer to questioning everything we did in part 1 and by that I mean whole decision to save Ellie instead of looking for cure.
Now it would be pretty insane plot twist if whatever has happened in TLOU2 made Joe think that they made mistake and finding cure is only way to save humanity? And once you are reunited with him he pulls absolute betrayal?
That would be one of most shocking moments in history of game storytelling.
As far as narrative go ND doesn't make weak games and I think last thing we can expect from them is simplistic story.
I think you might have a good point that it's building further from the dilemma in the original. However, that seems a bit dubious how that'd work, considering we know from information that should be pretty reliable in the first game, that there wasn't a guarantee of a cure at all and that they had experimented with others. Making Joel regret his decision just wouldn't jive well and would definitely be a hated decision. The guy had no interest in saving humanity as a whole, furthermore he made that choice then and deliberately lied to Ellie about it. Making him undo it is just a shitty plot development outta nowhere. He's had many years with demons and brutal shit happening, so no one would buy him regretting his choice. Ellie became a replacement for his daughter, so he'd in no way betray her. Shitting on that would make the game utterly hated.
Rather, the big actual conflict would be from Ellie's side in my opinion, as she would definitely have a different perspective on it. From Joel's side the thing I could imagine is him being overly controlling, due to being scared to lose someone he loves again. You can see this shown in the E3 2018 trailer, where that one asian guy talks about how Joel really went in on him in regards to patrols, specifically around her patrols. It's also shown in the release date trailer in the scene that Joe shows up, that there doesn't seem to be any open animosity between them.
That might be something that cause a conflict between them, which could perhaps make for a situation where Ellie is being reckless or just encountering a group causing Dina to be killed. Tommy gets a lot of focus seemingly, which would entail that something is sort of off between them, albeit the release date trailer shows that Joel is alive (albeit none of the gameplay, leading to a bit doubt as to whether Joel dies and it's from before he does, which I imagine would fit the trope more, like Joel dying saving Ellie from the winter events that lead to Dina's death. However the city environments make it seem like it's further along in the story, making that less likely, and it further shows that there's no big animosity between Joel and Ellie). That's a typical trope, but it can work since TLoU is about inter-human relationships. However, the cult element just seems much less interesting (and going by the E3 2018 trailer and release date trailer it definitely seems to be a cult, or at least something akin to it, which I feel makes for a rather boring enemy). A conflict with the fireflies would be far more interesting, because they have actual stake in the conflict with Ellie and Joel. Then again, we've seen the fireflies sign, meaning that the cult might just be a temporary enemy under one of the parts (it's also a seemingly matriarchal cult, which I guess is kinda new, but it's still a cult. Perhaps the aftermath of the first game, the matriarchal figure being Marlene?). It's clearly spanning time and multiple locations, like the first game.
ND definitely has narratively weak games, so I wouldn't say that there's any guarantee of things going well (at least 2 of the Uncharted games fall within this). Big "what you thought from previous game was all wrong" twists are usually ones that'll either succeed greatly or fail miserably, and usually the latter. So pretty risky, though I guess risky is better than being bland and by-the-numbers.
There's probably a lot of info if a timeline is made and further analysis of the material that's already released is done. Actually getting a good grip on the timeline would be most important, which seemingly from the released trailers, seems like it starts at Winter, but I imagine that's not the case for numerous reasons and ND might have released trailers in order to confuse us slightly as well. First of all, winter would make the events happening too closely, like she and Dina getting closer and then the events that seem like showing Dina possibly being killed during the same winter. Unless the whole community is a big open relationship community, that'd make the motivations of Ellie weaker. It'd then have to be more relying on their friendship as the main driver and perhaps Ellie's awkward position in terms of interest in Dina as connected to that and the newer developments.
Lots of questions.
Honestly, the big negative is that it seems ND is not taking many new steps in terms of gameplay, other than enemy encounters seemingly being improved. I'd say that's pretty typical of ND, taking very small strides on the gameplay. In TLoU it was somewhat forgivable, being the first iteration, and it being a natural sidepath from Uncharted 2. However, TLoU2 needs to evolve the combat and possibilities and not try to coast on story alone. It's okay to have a minimalist HUD, which is something ND did well with TLoU. But that doesn't excuse a minimalist overall design.