Well this game is pretty well-known as play as you want casual in all but the most difficult Savage and Ultimate content so no surprise people make such parties for kicks lol and as long as the toughest content still requires the trinity I doubt SE will mind people doing so :P
Outrage never stopped SE from doing things before lol but we will see.
I still don't think SE would give us "clone" jobs, but if they do they wouldn't be added as an advancement of an existing job. That would mean every other job would get an advancement too, and that is way too much to do and is like trying to replace every job we have. Besides, there's no reason Viking wouldn't be a completely separate job from Warrior, because it would be. Also if they did add a Viking job it'd like begin in Limsa Lominsa due to it being relative to pirates and stuff, but would not require Warrior be unlocked to unlock Viking.