I have played FFXI for over 5 months, EQ2 for just over 2 1/2 months, and WoW for about a month and a half, heres my two gil.
In EQ2 there is no "Blink Tank" like the Ninja in FFXI, the tank subclasses are: Crusader (advanced: Shadowknight/Paladin), Brawler (Monk,Bruiser), and Warrior (Berserker/Guardian). You start out as a fighter, at ten pic Brawler, Crusader, or Warrior, and depending on alignment at level 20 advance to your next class. Warrior however can choose whether or not he wants to become a Guardian/Berserker. The closest thing to a WAR/NIN in ffxi is probably a Berserker in EQ2 because it can deal some dmg, and take some dmg. Also, Fighters get duel wield at level 10, so no need to worry about toatin around two axes ^^. As for stealthy, you can check out the scout classes, but basically all have some degree of cool stealth moves to them (back stab, ambush etc etc) I'm not real sure about the throwing weap question... rangers obviously excel in doing damage with a bow, but as for assasins... (another scout class) i'm not sure how they rate as far as the throwing weap area goes.
Groups in EQ2 are so much better then FFXI, first of all there are way more cleric(healing) type classes in EQ2 because they all have there unique way of healing, and to put it bluntly sound and look alot cooler. A fury sounds 10x cooler then "White Mage" imo. Groups feel more fluid in EQ2, if someone makes a mistake, it wont destroy the entire xp experience, and everyone get mad and disband. Truthfully you probably wont even notice it.
As for WoW... you solo most of the time, and as someone previously stated, its not a "hack and slash" game, but thats what it feels like due to lack of depth. if you play on a PvP server you may like it, but WoW is a completely diff. feel from FFXI. where as EQ2 feels like a upgraded, better version of FFXI in a way. I would recommend trying both just because it differs so much from person to person, but if you can only try one, i really recommend EQ2. If you do join EQ2, I'm on Oggok Server, char name is "Beowhulf" GL to you, hope you make a good decision ^^