It depends on what you mean by 'complexity' I think. Some peoples definition of complex and hard content, such as FFXI, just sounds like utter boredom to me. Don't get me wrong, I like to think of myself as an experienced MMO player (My first was actually FFXI back when it was first released here in the UK, but I stopped playing around five years ago) and there are elements of the OP that I would love, such as more character personalization and hybrid jobs (If only so my beloved Red Mage can be added...) but such complex content would need to be fun most of all, and perhaps not something shoved down every players throat. My personal greatest fear for a game is not things like DF or casual players, but an 'elitist' attitude or community.
My personal opinion is that there should be features and progression which caters to all styles of play, from casual to hardcore. I do not think it is fair for one to be singled out for the other. There needs to be content which gives players of old a challenge and a reason to continue playing, but you still want to have a game which dose not punish you for simply being new or wanting to enjoy other aspects of the game (Such a story) over gear progression. From what I have seen of the updates, this seems to be the way SE flows. The problem is that whatever Yoshi dose, there will be people on both sides who will demand more and feel that they are left-out. It is the same with every MMO.