Heres the deal with autoattack. You cant just engage autoattack and then go afk, any mob that gives you XP will destroy you in no time. You could only do that with much much lower level mobs that you would not want to bother fighting anyway - but in EQ a level 1 skeleton would attack a level 65.
The reason autoattack is good, is mostly a visual and visceral thing. It engages people in to attack so it looks like and feels like they are fighting, and they dont need to actually press something for each hit. It would get really tiring having to hit every mob 20 times, especially seeing as you kill billions of mobs in eq. But those hits dont do much, especially as none melee dps characters. It's what you then click which does the damage and has the powerful effects, and you click those independently of the auto attacks. So it looks like an action packed fight, when really its people only using a few spells and abilities per fight.
For melee dps characters, the autoattack does do most of their damage, but there is some stuff for them to click too. It was very simple for those few classes, but they tended to occupy themselves with other things. Monks for example had little else to do besides engage auto attack and then press kick a few times. But they became the main pullers and would know the pathing routes and how everything worked, in every dungeon, and every raid. And pulling required effort and skill, so fighting was almost like their moment to rest, while everyone else gets busy killing it. Then everyone else sits down to recover after the fight, and the monk heads off immediately to look for the next kill.