Honestly I dont think this requirement will be very well received. The story does have its interesting parts but most of it is just complete fedex quests having you port all over Eorzea just to talk to someone about something or click on something before going back, only to go somewhere else. Ive been grinding out the story, with plenty of time, in order to be ready for expansion, and there were times ive wanted to gouge my eyes out.
Seriously, that whole moving to Revenants Toll quest 'chapter" was HORRIBLE!
I can just imagine how pissed off players will get when they have to do this knowing there is a whole new expansion zone that they cant get to because of some arbitrary b/s built into the game. Even worse for new players who'll have to grind out dailies over multiple days, already at level 50, just to inch their way to ilvl 90+ while they do the quest chain (which again, are like 95% boring fedex quests).
Just let people get to Ishgard and pick up from wherever the 3.0 story starts. If they miss anything they are free to go back and do it themselves. If they dont care then why would anyone else (particularly those who support this) give 3 flying flocks about whether or not someone else has? Put in an Ishgardian rep in each of the main cities to start a level 50 quest that leads into expansion areas. Simple. To each their own. Quite being such snobs about it, its none of your business how people want to play.
"You dont know about Iceheart or Shiva? Or the Uldah conspiracies? Or Domans? Hmpf! Nope. Sorry not sorry. GTFO!" ... seriously?