Wholeheartedly agree with OP. The iaijutsu is the main emphasis. Middling damage as you build up your resources, and then when enough time has passed, the further you wait and build yourself, the more devastating the final blow is supposed to be. That was the whole core of the rotation. All the other stuff they've added was just fluff that reinforced that idea.

Iai should hit hard. All of them. Crit variance seems like a poor reason when that was how the job has functioned all this time. Unintentional or not, several aspects of SAM gameplay has fed into the idea of samurai from the rest of the FF franchise. Iai casts being a direct active representation of Cyan's sword tech from FF6 and what not. Could even argue that the disparity between crit and non crit are akin to using Gil Toss in other games as damage from that is typically 'a gamble' unless you're filthy rich.

All I wanna say is, the kit in 6.1 feels limp. Sure, trash mobs still die in a reasonable time. Sure, bosses still take die in a relatively similar time. But the fun of the job is gone if the one thing we're supposed to build to doesn't have an impact.