What class is the, "story" class of each expansion?

[Adonan]

The ShB cinematic leads me to believe the DK might be the more lore accurate class to play through the story with. Is this a common thought, and what other classes would you consider to be lore accurate from each expansion and the base game?

[Vidu]

Well, each expansion had a "poster class", so to speak - mainly the class/job the Warrior of Light (the stand in for our character) took on in the cinematic trailer.
So that would be Warrior for ARR, Dragoon for HW, Samurai for SB and DRK for ShB.
I'd say you could argue a bit about ARR, considering how it had a bit more focus on an adventurer-party, with a warrior, whitemage, blackmage and bard.
Given the far eastern theme of Stormblood and Lyse being one, monk could also be considered a featured job for that expansion.

Its a running joke by now that the "poster-job" is the one that gets messed up the most in its respective expanion...

[TwiibieTwuu]

Monk for Ala Mhigo. Samurai for Doma in SB

WoL was two jobs in the SB trailers

[Eloah]

HW and SB are also unique in that there is a poster NPC for those jobs as well, Estinien, Lyse, Hien. And while it seemed like it might of been a trend since it happened with back to back expansions, it might be more it was convenient for the plot more so.

Also there have been 6 representative jobs in total thus far. 1.0 is represented as an Archer. This was shown in the latest Rising event cutscene.

[Enkidoh]

You mean the class or Job 'Derplander' has in each opening movie? It varies, but it's more or less like this:

1.0: GLA in the Adventurer's Guild but changes to ARC within an Echo scene
ARR: WAR
HW: WAR then changes to DRG during the defense of Ishgard
SB: MNK while training against Lyse in Rhalgr's Reach, and SAM in Kugane
SHB: SAM during the Battle of Gymhlyt Dark, then cycles through ARC, WAR, DRG, MNK, SAM and finally DRK while fighting the Sineater in the First.

[Derio]

Archer for 1.0 till about 2.1 then the rest of ARR is Warrior. Then DRG for all of HW. Monk for the beginning of SB and Samurai for the end. Then DRK for all of SHB.

[Sated]

Archer for 1.0 till about 2.1 then the rest of ARR is Warrior. Then DRG for all of HW. Monk for the beginning of SB and Samurai for the end. Then DRK for all of SHB.

It's these ^

These are the jobs that were reflected in the anniversary event cutscene, which showed your character as each of them.

[Averax]

1.0 -> BRD
ARR -> WAR
HW -> DRG
SB -> MNK/SAM
ShB -> DRK

One day, it will be a DoM class

[MoofiaBossVal]

The Dragoon 30-50 storyline establishes the lore of the Azure Dragoon. It establishes Alberic and his successor, Estinien. Playing through HW as a Dragoon feels thematically right, as you knew Estinien for longer and knew his struggles.

The 50-60 Red Mage storyline gives you more lore on the revolution. If you play SB as a Red Mage, then it can feel like you're the disciple of a fallen order, returning to set things right.

Samurai doesn't have much to do with Stormblood. The connection is tenuous at best. I thought that (60-70 spoilers)
[spoiler]The student of Musosai's who turned evil would be Zenos, but it turns out to be just another NPC[/spoiler]. The only real parallel here is that Zenos wields a katana too.

The Dark Knight story doesn't really have anything to do with the story of Shadowbringers. They are only aesthetically similar.