SMN/ SCH, because I absolutely abhor pet classes. They never feel like "an extension of my self/ class" or any of that stuff they like to advertise but instead like a dumb pile of pixels I have to sent from A to B and tell it how to breathe because it doesn't get anything done right by itself.
Also the whole excessive number throwing and "more intelligent than thou" during the ARC quests and even some SCH quests really put me off and I found it incredibly annoying because it felt so forced and overdone. SCH quests were generally much better and I liked the story with the tonberrys, fairy and wanderer's palace but the class theme in general was just not my thing.
Other wise I think I'm okay with most classes. I don't see myself ever really getting into NIN or WAR, but it's not as bad as with SMN/ SCH, where the class theme just gets on my nerves und I want to strangle my fairy/ egi.
You are a turret. Turrets don't move!
I love having BLM in my party. Though they need some extra attention, at least I always know for certain who's gonna be targeted by all the aoes. Escpecially once the leylines are down. Let's take a moment to appreciate our involuntary mechanic soakers <3