Dat Ninja stuff, again.

[Nalien]

If you took Arcanist to 50 before fighting Ifrit in the story, you could not do the quest for Summon III, or Summoner in general.

If you take Rogue to 30 before doing 2.2, you likewise probably wont be able to do the quest for Ninja. At least in my opinion.

You cannot start a character as Rogue - You have to find their Guild, which was recently described as being similar to XIs Tenshodo; access to which was eventually required for progression, at which point they handed you an invite, you could however join up before that by finding it.

Quest dialogue for 2.2 can be altered based on whether you have found the Rogue Guild or not; If you have there is new dialogue with you and Thancred introducing Yugiri to them, rather than Thancred being the only one knowing them. If you haven't, you get what we currently had, with the quest basically pointing you in their direction as well as Yugiri.

Quest dialogue is already altered based on a number of factors; Legacy account and Jobs being the primary ones - Doing the quest for Lost City access will provide different dialogue based on whether or not you have completed the White Mage quests or not.

World progress is a iffy thing. Mor Dhona has changed, sure, but NPCs haven't. If you have not completed 2.3s main quests, Rowena and various NPCs around Mor Dhona do not comment on the formation of the Crystal Braves. Likewise, if you have not done the quests, Crystal Braves officers aren't in all the city-states. If you haven't done 2.2s quests, Doma refugees are not around the place. If you haven't do any of the 2.1 content the Scions are still located at their original base rather than Mor Dhona. The world doesn't progress entirely with the patch number, for the most part it's based on where you are in the main scenario.

It isn't a simple matter of "It's patch 2.4, so the world is in 2.4", if you haven't touched 2.2 there are no Domans in Eorzea, even if there are on other peoples screens. On the new players screen, they don't exist. Mor Dhona has just been built up by the Adventurer's Guild, and after 2.2 they get a helping hand from refugees and some Domans pop up around the place, like we all currently see.

People might see requiring 2.2 completed to unlock Ninja as unfair, but honestly, those same people will probably complain about needing an expansion to get the expansions Jobs, and claim they're Pay 2 Win. Having requirements for content is a good thing, it fleshes out the world and makes it seem more alive, dropping such things for player convenience has the opposite effect. Just look at the Duty Finder; that is solely their for player convenience and it makes the world feel utterly dead and disconnected. Yes it's convenient not to have to head to Camp Tranquil every time you want to enter The Lost City, but as a result all the dungeons in this game don't feel like they're part of the world at all.