Quote Originally Posted by Cairdeas View Post
That isn't true. the Terminology is older then MMO's. so is the "Trinity" though in FF's its never been a true trinity. Its always a Mix of 6 roles.
The terminology is older than MMOs because it was present in MUDS, that are nothing else than an early incarnation of MMOs. It has never been applied to offline games simply because roles (as you yourself stated in more words) are much more elastic there.

That's why you can't apply most single player concepts to MMORPGs. Roles are less elastic and depend only on a single player's will. You can make almost any character a "tank" in a single player game, and be content with it regardless of efficency, because the only thing dependant on that decision is your own enjoyment.
Roles in MMORPG are subject to quite a lot more restrictions, as stricter balance come in play.

But no worries, I can amend my statement if it makes you happy. Dark Knights have never been tanks in Final Fantasy MMORPGs.