I personally enjoyed the main scenario quests, but was pretty annoyed by some of the NPCs. What I got out of the Main scenerio quests (spoilers ahead):
Minfilia is just the worst. She is the ultimate "damsel in distress" cliche, and I have no clue why she is in a position of leadership. I kept hoping as I progressed through the main scenario quests that she'd do something, anything, but then I got to the last series of main scenario quests and what happens? She gets kidnapped by an Ascian... *Sigh*.
Alphinaud is just plain boring. He has absolutely no personality and I could mistake him for anyone else I just briefly met as I passed them in the street. I really hope they either ditch this NPC or add some quests that flesh him out to at least make him somewhat relatable, instead of the political string-puller that I see him as now (really, I started to think throughout the main scenario quests that they'd do a switcheroo, and Alphinaud would turn out to be a traitor or a spy because I just didn't understand why else they would make an NPC so boring to the point where you just dislike him).