There's an infamous quote by one of the Wildstar devs who said as many as 65% of MMO players prefer to play solo and that they're an under-served market.
I don't think I fit into any of those categories. I like a persistent world with continuous content updates, I like seeing other players in the world, I do not like being forced to group with other people. FFXIV has pushed me out of my comfort zone and I can't honestly say I've enjoyed it. Everything but the mandatory grouping I've liked, unfortunately there's no escaping having to do dungeons and trials (currently). Once I got to ShB I was absolutely thrilled I only had to deal with others for trials and duties in the MSQ became enjoyable rather than something I'd dread and sometimes put off for days.
I wonder if this means CT will no longer be mandatory. I don't see how you make FFXIV solo friendly and still thrust players into a 24-man raid.
I think HW and ShB were, the others not so much. I still think the devs need to work on ARR a lot, particularly when it comes to spreading out job abilities so you're not just hitting the same 3 buttons for 50 levels. I didn't like the story of ARR at all, that's subjective but I don't think ARR is a good enough hook to keep people engaged.