I can't really agree with lumping 12 with Shadow Dragon and Awakening.
I can understand that, it's really a matter of personal preference. 12 is absolutely a tier above the other two... I just generally find it unremarkable and not significantly better than the others. Don't get me wrong, it IS better in my mind, but it still has that godawful art style and feels pretty threadbare to me (just not as much as SD). It's not bad but I still think it's very much part of a low point in the series, three uninspired games in a row with a number of significant failings in my eyes.
And part of the writing problem is that the games are trying to tell stories with scopes too big for the games they are in, and they dropped narration so you don't get any story details apart from the scenes with your characters.
Awakening's so bad about this, telling three stories that have no time at all to breathe so they all just sort of happen one after the other without any of them feeling properly concluded. It probably would have been fine if they didn't decide they had to have the Valm arc for that weird bit of FE2 nostalgia. As it plays out, half of the game is basically a DLC campaign that concludes with a whimper and then is followed up with a rushed return to the original plotline's dangling threads. The generation mechanic also doesn't help matters, it just bloats everything significantly and basically doubles your already very large army, further diluting everything else in the game.
Fates, I think it could've been fine with its stories if they would've just given us some idea what the world is even like. But nah, they didn't care about that, instead they felt obligated to keep the second generation mechanic because it was a part of Awakening's success, bloating an already large project by requiring tons of retainers so that you can run around shipping your teammates, and a ton of kids who don't even make sense to the game. At least Awakening had a time travel thing, Fates just has a goddamn baby dimension. But yeah, I think the plots could've worked if they A) actually informed us of ANYTHING about the world and B) didn't have so many superfluous characters that had zero relevance to anything. Instead of focusing the narratives to all make sense and feel whole, they wrote a ton of empty characters. Hell, remove half the characters in the game and maybe the remaining characters actually get some manner of halfway decent characterization. Do we even need four siblings in each family?
FE7 has more chapters and has narration that tells you about the world. Not amazing worldbuilding, but offers a lot more than Fates and Awakening did.
I wish we could've had at least that in Fates or Awakening. In general I think FE7 is fine with its narration because it gives you what you need and it was designed with a pre-existing world in mind - if the whole world got FE6, the narration would be simply refreshing us on things we already knew from 6. When it came to the relevant areas of FE7 (so... Lycia and Bern, really) I think it did a really good job with its world-building, a lot of time was spent with political leaders of the states you're in for a chapter and often those areas would be discussed before and after that chapter. If nothing else, you'd at least hear one story-relevant character mention a region before you go to it and you'd have some idea of what it or its people are like based on how it was talked about. I think it played its politics well and the political situation basically was the game's major world building.
Meanwhile, Fates shoves you in an area and says "yeah these people have magical wind powers for some reason, have fun" and all I can think is that I only just learned this place even exists and it was never hinted to me prior. Hell, thinking on it now, I don't even remember why there was a conflict between Nohr and Hoshido in the first place. I know there's the whole thing with kidnapping Corrin/Azura etc, but that wasn't even the start of their rivalry. It just seems to be the thing that sparks the current especially bitter part of their feud... and it seems to exist purely because "lol Garon is comically evil for the sake of being evil". It feels like they've got generations of hatred between each other but the only info we even have is kidnapped kids, and the hatred predates that.
FE9 and 10 are easily the best examples of good worldbuilding in the series, at least since the games started getting localized (can't speak for anything before that). Those had good narration and the overall story was split up between two games, each with more chapters than Awakening or Fates, allowing for more opportunities for the player to learn about the world.
My favorite thing about these games actually, the Base conversations. Tons of additional world-building conversations to flesh out characters and the world. I'm so disappointed that wasn't brought back for Awakening or Fates, it could've helped them out so much and it was my favorite new thing added to FE in PoR. The main plots of Awakening and Fates would still need to do a fair bit more work than they actually did, but Base conversations would've made the scope of things so much more manageable by allowing us to digest what's going on while giving us reasons to care about the places we were going to.
It's like... FE isn't amazing writing or anything, but it can be very entertaining and full of a lot of engaging/likable characters. I love FE7, it's one of my favorite games of all time, and I really enjoy quite a bit about its plot and cast. Path of Radiance I feel similarly about. With Awakening and Fates we don't get any of that anymore and it just feels like there's very little to remember, which is bizarre considering the general outlines of the plots feel like they should be bursting at the seams with memorable moments.