The OP agrees that content is a big issue.
I don't like saying there's no content because there is and its called Leves.
The problem is Leves are great for casual to moderate players and a nice boost when they're available to hard core players - but they aren't very diverse and they aren't very immersing, but in order to make them immersing you'd have something more like XI - where you find an NPC, talk to them, run out somewhere, fight something, gather a material, run back - and leves (while not as immersing in the game world) streamline a process so someone with 15 minutes can do more than one of these even.
So the argument shouldn't be "this game isn't casual friendly" or "has no content." It should simply be that a wide majority don't think the game is fun. That's what it all comes down to and I know "fun" is subjective (I have fun in XIV ever day!) but if it can't keep most people playing then something (content provided seems the usual suspect) is very wrong.
I just think a lot of times fan outrage is misguided or poorly worded.
Just for fun let's play devil's advocate and find ways the game isn't casual:
Market Wards - since their inception they've been more inefficient than an AH (they've since gotten extremely better) showing that if you were casual you'd have to waste a session of time buying an item.
Repair System - You could never repair things yourself; you'd have to rely on others to repair your gear, and this could also take time. You could make friends but this leads me to my next point.
Community - If you're a solely casual player it's that much harder to sustain friendships with those other than your RL friends. There is no time to group up with buddies, which is ultimately the point of an MMO.
This makes a casual game, but without the MMO part.
I agree with the Market Wards, but it is primarily fixed now. I think we all knew the Wards would be fixed and it's a matter of complete douche-baggery they released the game in the state it was in (particular Markets). Even selling to NPCs (and moving things to/from bazaar/retainer/retainer's bazaar) took an absurdly long time. I spent about 5 minutes standing in front of a NPC vendor dumping 60 pieces of crap I'd "farmed" while leveling to 15. 5 minutes to item-dump is terrible. But anyway this is (and has been) on the up and up since day one. So hopefully a think of the past and forgotten in a year.
Repair System - I disagree. It depends entirely on the player. My wife is a casual player (not a unicorn). She works too much during the week. She may do 1 behest before work and 2 after work (not playing in between, but cooking dinner) and the "meat" of her time in the game is on her days off. She plays 10 hours a week total (plus those 15 minutes here and there at Behest).
She keeps pace with me on her main job (and I am pacing myself but not to allow her to catch up because 2 Ranks per week is pretty ambitious in my opinion) but also manages to have 2 Craft Jobs to R20. If she had done research (or I had done it for her!) she may have chosen to Rank up 1 Craft (Weaver) to repair her gear. She'd still have to repair her 1 Weapon at the NPC (but only 1/week!)
The repair system isn't that bad for casuals. Though it does require a bit of planning and deciding what kind of armor you are going to be wearing and how you can best repair it.
Community - This is kind of silly. Grouping up with buddies is the real boon of an MMO but it certainly doesn't need to be a "friend finding" tool. Using my wife as an example still even if she only had 1 friend (me) it's more than enough to keep her going. For example, I'm a Carpenter (R32) so that covers her weapon. She (fortunately) doesn't even need that 1/week weapon repair. Even if you only had 1 friend in the entire server (and provided you could always play together) you'd be fine. Would it be the best way to experience an MMO? Not in my opinion, but maybe for some people that's fine.
Though it probably isn't. I certainly wouldn't design an entire game hoping that was true. So you have a point, but it's not ... eh It's debatable. The community, I mean.
Oh and the trade off (just for comparison's sake) between me playing 5 hours (or more) a day and her playing less than 1/day and 10-12 on the weekends is that I do have a R32 craft and several 20+ jobs (Well she also has 22 Miner, so even still she's not that far behind me). You know? She's living proof that a casual can get a lot done in a moderate amount of time - and she doesn't even make the best use of that time! like leveling a craft that didn't really benefit the Magic job she chose.