For the most part I like how they've taken to doing deeper dives on the characters as the expansions go on. When playing through the ARR sections the Alliance leaders felt pretty meh, although the development for Raubahn and Nanamo has been fantastic through Heavensward and Stormblood. Unfortunately Merlwyb and Kan-e-Senna haven't gotten the same development which is a shame since, especially with Merlwyb, there's definitely opportunities. There were some nice almost there moment for her in the ARR patches, but as the action has moved further away from the main 3 city states the opportunity hasn't been there.
The Scions have definitely grown on me too, again going from 'meh' to looking forward to seeing them in the story. Papalymo was my fave in ARR just because he had so much personality between the lala emotes and his voice actor. It set him apart in my mind from the others who were more like fantasy trope archetypes to me. A lot of that is probably due to the writing team being able to take a breath and tell a story with more room for small character moments vs writing ARR where there needed to be a lot of narrative shorthand due to all the world building for people who didn't play 1.0.
It's been neat to see that development too. Seeing Alphinaud going from someone who was the worst "I'm the smartest person in the room" to a more measured diplomat was one of my favorite transformations. Same with Urianger who's a very nuanced characters in that his emotions come across in a much more nuanced way. Shadowbringers gave us a nice look at him feeling conflicted about not sharing some information, but at the same time there's no doubt that he's just as dedicated to the task at hand.
So it's definitely not the deepest narrative in a piece of media, but I think the writers have done a bang up job developing the characters who initially felt a bit one dimensional and then introducing characters like Emet Selch who feel more developed on arrival. When it's time to work with the Scions I look forward to seeing them again. I love being able to talk with Raubahn and the other Alliance leaders (although man, can we get Merlwyb's ARR VA back pleeease?), and I'm even looking forward to what they do with Zenos going forward. I didn't think that I'd like Emet Selch when he showed up in Stormblood, but man he made me love him in Shadowbringers, so I'm hopeful for Zenos to get interesting.