Why vertical progression is poorly implemented

[CyrilLucifer]

and if the number of "former FFXI players" I've met in the last decade is any indication, while it was a wonderful world experience, it wasn't the best system for retaining player interest.

That's a horrible, horrible, absolutely abysmal reasoning.

FFXI is more than 12 years old. Do you honestly expect people to play the same game, with the same amount of love and passion, every day for 12 years?

Of course they are former players. I have absolutely absurd amounts of time devoted to XI and even I get bored of it, no matter how much I love my friends there and how long we've been together (I've had friends from XI for more than 10 years that I still talk to).

In fact, you've basically proven the opposite point: XI is still P2P and still retains a decent number of subscribers after so long. If anything, that shows that whatever it is doing, it's doing it right. I don't see modern XIV lasting even half as long as XI in its current state. That being said, a pure jump to horizontal is unrealistic, hence why I propose at least starting with something as simple as "more options" and "more variable stats." You know, like every other MMO in existence.