I haven't played MMOs for a very long time, until recently when I started FFXIV.
I played the trial of FFXIV and started as a Warrior as normal (I usually play the strong, 2-hand weapons type of character), but I hate tanking. After realising the Marauder was both a tank class and boring as all fuck, I tried out some other classes and eventually landed on Arcanist.
In the full game, I'm currently a Summoner. As far as I can tell, it's as close to a Warlock as FFXIV gets.
I just love having to manage poisons across multiple targets, and managing the pet (using AoE in appropriate places, etc.), supporting healers with my crappy heal when they forget to do their job or waste all their MP, and healing the pet too. As it's developed I've got buffs to think about, as well as my own AoEs and abilities that play off of others.
Basically, there's a lot more to it than pressing the O button and then pressing the X button sometimes, which seems to be an issue most of the melee classes in FFXIV, and MMOs in general, suffer from. (Even looking at end game strategies, for some classes it's just a case of using attacks in the same specific order until the target dies. No thought. Not fun.)
My experience with my WoW Warrior back in the day was much the same. Hamstring, Rend, mash Mortal Strike and wait for my UI to tell me I've critted so I can use Overpower. 8 4 1111111111 7 111111.
That's as deep as it ever got. Hell, it only got as deep as that quite late into the game.
The worst part was everyone asking if I was a tank, and nobody ever wanting a DPS Warrior.