I really agree with the OP. It's a great strategy and somewhat emulates the success Blizzard has had in balancing different skill levels of players. If they can avoid the "content is dead after the next patch" syndrome, then it will be a successful design.

As a side comment, I absolutely find it hilarious when people trash WoW for being too easy, and then I see how poorly they perform in battle settings in FFXIV. It blows my mind.