I don't think people are looking for a grindfest, in fact, we currently have a grindfest in place, it's just a very short grind of repeated content, it's dull, it's tedious, it has no longevity (it's why DD was so popular till it was fixed). What people want in an MMO is a storyline that is longer than a single player game. You could start a new save on Skyrim and still have not completed the main story by the time you're level 50 with a relic in XIV.

MMO's like GW2 have reasonably fast levelling because the content at 50 is PVP focused, you want to get out into the world and kill people so getting you to 50 so you can participate in the PVP is a prime focus. With PvE focused games then it's the journey that is important and not the destination, you want your players to take their time getting to the end, especially if the end is as weak as XIV's currently is, and will be for an uncertain amount of time (4 months? 7 months? The next expansion pack?), so you give people things to do and aim for, you have gear at certain levels which last a long time, so you take time out from levelling to obtain that gear.

With a method like that you can start with weak end game content, with the current system you have people grinding away, getting their jobs gear maxed out or, worst case, logging on once or twice a week and then leaving the game to play another for fun.

FFXI did things right enough.

Crafting to cap took a lot of time and a lot of expense, not 1 day to get from 1-50.
Enforced breakpoints (limit break quests you had to complete, with Maat being either a wuss or a monster depending on your job)
Levelling currently is too fast in XI, you can go from 1-99 in a day if you have the boredom.
Gear, there could be 2 BiS items, one for TP one for WS, you would spend a while obtaining the items to maximise your job, in XIV it's.... yeah
Things to actually do, this could be a weakness of XI, there is so much you can do that it sometimes feels overwhelming

With XIV, knowing the number of subscribers is only half the knowledge, knowing how many people are logging in 4+ times a week would be useful (a lot of people may have gone for the 180 day subs for the items, and now don't really play as there is bugger all to do). So yeah, MMO's keep people subscribed by giving them plenty of stuff to actually do, if people find they log in to a game and can either grind up another job to 50 because there really isn't much else to do, they are not likely to keep spending money to play.