As much as I play the game every night, I still consider myself a casual.
While I play the amount a hardcore player would usually play, I still don't make myself believe I have to be on every night, or in a LS that demands my time. I go out, away from my computer, without feeling of regret that I am falling behind in FFXIV, at least not yet. I love how this is set up, at least so far.
As someone said beautifully, since you are a casual player, doesn't mean you lack the skills and organization a hardcore player would. It simply means that you cannot put the kind of time a hardcore would. I think the main difference is that hardcores are more ahead of the game. If you can't handle the difficulty a game presents to you, what do you do? Play a game that does cater to your difficulty.
I say this because difficulty is one of various things that keeps a player addicted to an MMO. You have a tough raid to beat, you keep coming on in hopes of overcoming it, and when you do, you keep going until you get the gear you want. If you take away the difficulty, the content gets blasted through and developers can't keep up with giving you more content. People feel less of an incentive to play if they have all the best gear without much effort put into it. Not only that, it takes away the rewarding factor of the game, which FFXI actually excelled in.
I will make another WoW comparison here.
Firelands is currently the newest and most difficult raid in WoW right now, and the game having 11 million+ subscriptions, obviously a portion of that are casual players. WoW has set up a way that raids are hard, fun, rewarding, and accessible by anyone hardcore and casual, and can play them based on how they like to. Rather it being one time a week, or do a portion of the dungeon in one night, then more later that week, this is balancing hardcore and casual play, while being difficult and challenging at the same time. Not to mention, they made raids that satisfy people the majority of the time it takes till new content comes in.
Point I am making is, if you make content easy, people will blast through it, get bored, and stop playing till something new comes in to blast through. Content needs to be difficult, and at the same time, cater to a hardcore and casual player's interest. This is actually a problem with the Darkhold dungeon in FFXIV. While I myself have not gotten every piece yet, most hardcore LS's have already gotten everything they need for all their classes, and I believe they are just doing it for the hell of it now. Or rather leveling classes, just so they have reason to go in again. Then again, Darkhold is still more of a dungeon than a raid, I don't believe major end game raid content will work exactly the same as a dungeon. I want content I can set a long term goal into till newer content arises.