Leveling is a phase that you go through when you first start your job, what we really want is live the experience while we go through that phase. I support both methods, I lived both methods and I really enjoyed them. but I support the Grinding movement, because I mainly want to relive that experience again.
Here are the experience:
Grinding. Lived through my days in XI, and brother... it was a blast. Valkurm Dunes, Qufim Island, Yuhtunga Jungle, Altepa Deserts, Kuftal Tunnel "damn Guivre", Boyahda Tree, Sky... the list go on and on. XI's players and I one of them, wants to relive these days again. Every time you entered a new area you are experiencing something new with all the environment around you, you learn what to avoid, what to kill, where to gather, or where to go. Grinding gave the sense of accomplishment for every DING!, with every new chain kill you do, you acutely stare at your experience bar while it grow, waiting for that DING to equip the new piece of equipment you have been saving in your inventory. Grinding gave the meaning of your max level, because when you look at your max level, you remember what you acutely did to earn that level. Grinding gave us the opportunity to meet people, people you would would really like to join and you look up their names every time you decide to go Grinding again. I can go on and on about what I loved about Grinding.
Quests. Lived that in my Vanila days in WoW, and it was a damn great. Ashenvale, Hillsbrad Foothills, Desolace, Feralas, Stranglethorn Vale "long live hunters' camp", Tanaris, Silithus, and what was introduced in later expansions. Quests created such an interaction we never experience. Finding the other side doing the same quest created this mini game in your head, waiting for the other one to make the first move that would initiate a war that could create a massacre when things get messy. Quests created this schedule of what you wanted to accomplish with the given amount of playing you are willing to give. Quests with friends gave a new feeling for completing tasks, working your best to clear an area, the coop you end up doing was what made Quests.
Both can be viewed as this mindless task:
Grinding looked this mindless-non-changing-same-monster-same-area-killing. But the way I look at it is this task that you keep doing to perfect its execution with the role you are doing. How do you kill each monster with the perfect execution that granted a non-stop experience. The amount of damage and healing that granted the party the conditions that wouldn't let them stop and lose their chains and therefor maximizing their experience gain.
Quest looked this mindless-clicking-kill-gather-copy-past-dialog, But it looked to me as this stress-less tasks that I can work my way as I liked without the fear of someone would screw things up and ruin my time that I have planned. I had the opportunity to see some areas I would never step foot at if it weren't for the quests I'm doing.
Now, from what I have read, Quests seems the "effective" way to level, does that mean its the fastest way?. And it seems Grinding would still be a way to level but you are far better doing quests. Here what I don't like about that statement, it seems to me that they are acknowledging the Grinding but they want people stop doing by trying no to improve the flaws about that system, grinding has it flaws with over-camping, TP-burns where mages and tanks are left out, and more other could point out. It seems they worked around the flaws of Quest and worked that system to be more effective way to go, which seems unfair to me, if you acknowledge a system of leveling you should try to make that system work its most effective way for those who would go through that way.
In the end, people will just do what works for them. I had the chance of having all my jobs maxed for the 1st week when they introduced chain exp in 1.XX "can't remember the exact number", with WAR wolf camp style. But I refused, I want that experience again. I still dream of doing Grinding again even if its not the fastest way to go, I want to look back at my job level at the end of the day and remember what I acutely did to earn that level, even if the other person maxed his job and got that item faster than me, I've spent a year and half of XI game play, and I'm willing to spend the same amount for XIV. In the end, I just want to look back and remember what I acutely did not what quests that I have completed. I'm just 1 voice in this game, and I hope that would help.