Keep in mind my experience was the first 2 years of NA release.
I actually really enjoyed the leveling in ffxi for some strange reason. Perhaps it was that every group had to communicate, from weapon chains, trick attack, to whether the casters had enough mana for the next pull in order to optimize the speed of killing. Since every enemy could kill you and because death came with such a high penalty (especially after 60), there was a certain thrill of the fight because there was some real danger to it. Also, you always wanted to perform your best, because a bad rep meant it was more difficult to find parties in the future. And since everybody in the group just wanted to kill as fast as possible, everybody was all on the same page. You didn't have some people wanting to open all the chests for gear, and others wanting to play it safe, and others wanting to do speed runs, or others running around in spiritbonding gear purposely gimping your run. It got even better the higher level you got as bad players were weeded out in the lower levels.
Of course the drawback to all that was that you needed a party (usually a competent party) to do anything for most jobs. Which could mean hours of waiting around LFG. And while the death penalty provided a thrill to play with, since it did actually hurt, you had to deal with hours of progress lost if you get a bad party. And it was overly punitive after 60, where a single death could mean as much as a day's worth of progress lost, which could only be mitigated adequately by a specific class (only WHM had raise 2 at the time).
But FFXIV is a different animal. At its core is the idea of accessibility. Ease of leveling, ease of grouping, ease of gearing (ie: myth to buy the best equipment from running entry level 50 dungeons). A heavy death penalty doesn't work with that. Mediocre players don't either (because they pay to play too). And when you remove that, then you have to dumb down the necessary communication and coordination or it's going to lead to a lot of frustration. So for FFXIV, grinding would just be that. A mindless, quiet grind, worse than what fates or dungeons offer.
The FFXI grind was dependent on FFXI's unforgiving design. You take that away and it's just a mindless grind with nothing good about it.