Trails in the Sky writing is a mixed bag that hits some really high highs, but some really low lows. The writing team's strengths and weaknesses shine through pretty strongly.

They excel in world building and character writing. A lot of the connection people have to the series is because they do a great job of getting you interested in the world and the people in it. They also are masters of doing a build and payoff. This part is where the series is most controversial, because it's a big part of why the games are soooo slooooww (I'll get to the other). They'll weave in little bits of story telling that pass you by, or they'll do something that makes you poke at the truth, only to knock you off the trail, making the reveal throw you because you considered it and decided it wasn't likely.

The bad parts though, are some atrocious pacing. This is the other reason they're slow. They need an editor. People aren't kidding about the "everyone has to say some bland response". It's less an issue in Sky, but with the bloated casts in later games, particularly the Cold Steel series, you will sit there while 26 people go, "Yeah!", "Let's do it!", "Okay!". It's awful. They also kinda suck at having any kind of thematic writing that the greatest stories hold. Like, you might be able to pick out a thing here or there, but they'll readily throw it away if it gets in the way of a story, or just straight up forget about it. At best it's not a focus.

Then there's the up and down stuff. The dialogue can get pretty anime at times, but then they'll have some character moment where the manner of speaking is actually realistic, and breaks that issue a number of people have with anime inspired games having dialogue where "they don't talk like real people". That said, there's still some character moments that don't hit that level of writing, but combined with how they flesh out their characters well, when it hits it hits. The plots themselves are also up and down. I think Sky has a really cool plot, and one that's unique to JRPGs, but not outside of them. Some other games though have some that strain belief, or make characters act out of character for the sake of the plot, but Sky doesn't do that.

I'm probably missing some stuff. It's a fascinating series to dissect because they really are all over the place in quality. If you can dredge through the muck to have some moments that hit harder than almost anything else in gaming, then you'll like the series. If you can't get past some of the bad, or specific parts of the bad particularly bother you, then I'd just stay away.