If you could change one major thing about the plot in every Fire Emblem installment, what would it be?

[Rezzy]

Yeah, I did catch up on the forum after making my blind post. I agree with you on the join time and supports but I would rather she would start off as a sword locked class to make her seem more like a lord, or maybe a sword stave class like the princess in Holy War. While the rally idea is a good one that makes senses (and would be admittedly better for gameplay), I still just see her as a sword unit that promotes to a Pegasus Knight in my mind. Mist also promoting into a mounted healer kind of just makes the whole thing confusing.

She seems like she would lean more towards healing than offense, if she had to choose one, especially that early in the story. I think going from Staff to Sword makes more sense than Sword to Staff in her case. If she had been a more aggressive character, the opposite would be more appropriate.

I think Mist should have gained access to Light Magic, instead of Swords. I'm not a fan of only having one unit with access to a weapon type, and I often feel forced to use Mist, since only she can heal the BK fight.

[NekoKnight]

I'm pretty sure this was just supposed to be a red herring to add some tension to the story, and was never meant to amount to anything, given that everything else points to Elbert investigating Darin after being informed of his plans and getting in over his head.

Considering this information comes from Erik of Laus, it's a safe guess to say that he didn't fully understand the situation or was telling a skewed version just to spite Eliwood.

[Rapier]

FE7: I'd rather they follow the Magic A = Magic A trope.

My problem is not with the characters or quintessence. My problem is with how the game contradicts itself at some parts, like when Nergal says he needs Ninian and Nils to open the gate, then says "guess what screw it" and opens it anyway in the end, even without the established prerequisites for opening it. Ninian's ressurrection was also pretty convenient. If the game didn't want her to bite the dust, maybe they should've said she suffered a fatal blow and is on the verge of death instead of stating that she died.

FE10: The Dawn Brigade deserved more game time.

To be honest, I'd prefer if FE10 was only about the Dawn Brigade, expanding part 1 into a standalone game, like FE9 is to the Greil Mercenaries, then leading into another standalone title that would include part 3 and part 4's stories, but I understand this isn't plausible, as FE10 didn't sell well and FE9 had mediocre sales iirc.

FE13: Pick one arc, discard the rest. I'd prefer keeping the Gangrel arc, then incorporating some elements of other arcs into it. I'd not mind if FE13's plot was a War of Three Kings, ending with Gangrel's desperate plan to ressurrect Grima using his people and then himself as a sacrifice to bring an end to Plegia's enemies.

FE14: Return to the premise of the games: A conflict of blood vs bonds, with Birthright being a standard FE about beating an invader and Conquest being actually about reforming Nohr from the inside, instead of passively going with what Garon says (I swear, Corrin is worse than Kururugi Suzaku in doing stupid things and being complacent with stuff they loathe).

Meaning...

No Vala.

No Candle Wax Monster usurping the Nohrian throne.

Characters intended as siblings from the beginning are siblings.

I'd like to change more things (senseless plot obligatory sacrifices for example) but I can only choose one, so I'll stop here.

[Sylphid]

I strongly disagree with this. Black Knight in PoR is the real problem, since he literally has no motivation whatsoever besides wanting to test himself on Greil, which I think we all agree is an idiotic motivation. It's only in RD where we see how him being branded drove him to feel isolated and depressed, and this led him to unhealthily idolize first Greil, then the maniplative Sephiran. Without that backstory, the character is garbage.

Personally I'm okay with that, since for me he's all about the threatening, mysterious presence (mystery I was perfectly okay with not having an answer to, incidentally), but I understand not everyone thinks the same way. Anyways, I do agree as a character he's pretty bad in PoR, though I don't think he's much better in RD anyways (in fact I think RD made him worse, but that just goes back to me valuing what he is in PoR and not liking the RD characterization he gets).

[Ema Skye]

Cut Chris, Robin and Corrin.

Most of FE 12, 13 and 14's problems are now solved.

[ALALALALALA]

Birthright: Flesh out the kingdom of Hoshido.

Conquest: Focus more on Nohr's resources and remove the hate monster cop out + the curse entirely.

Shadows of Valentia: Walhart references when?? 

[Kahvi]

FE 7: Make Lyn's story more than a glorified tutorial

FE 8: Err... I guess if I'd have to say something, the reveal about Jehanna's future king happened rather fast, pretty much none of the characters reacted to it and it was forgotten as fast as it appeared

FE 10: Remove Ike. Seriously. He doesn't need to be in this game.

FE 11: Flesh out everything more. Seriously, I understand that the game is old but that doesn't mean that the re-make has to be this basic. None of the characters really stand out because most of them get like two lines of dialogue.

FE 13: Make Yen'fay's actions more sensible and remove him as a dlc character.

Spoiler

He wants to protect his sister by trying to kill her allies, and quite possibly, her. They could've given him a better reason, for example protecting his kingdom instead of his sister by striking deal with Walhart, or something. At least his end was satisfactory but nope, they just had to pull out another Yen'fay from another timeline for some reason.

FE 14: Well. This one's obvious. Make Garon more likable. The story would be so much better if they wouldn't paint the hoshidans to be always in the right. The whole Conquest felt like an advertisement to buy Birthright.

FE 15: Convenient rockslide is a bit too convenient