People who say that fighting in MMORPGs is just randomly mashing buttons have seemingly never played against someone who is even remotely skilled. First of all, despite there being an auto-attack alot of MMORPGs focus on the skills of the character. There are different kinds of skills; buffs, debuffs, damaging attacks, DoTs, heals, HoTs and so on and you NEED to learn how and WHEN to use these!
For example in Guild Wars I'm fighting a Dervish with my Necro. The Dervish is a enchantment based melee fighter, while the Necro is a ranged damager or hexer. The Dervish begins casting an enchantment. I DO NOT cast a damaging spell! Instead I throw Spiteful Spriit at him, which causes casting to damage the players. Then he still casts more enchantments, which cause him to get healed. However I throw enchantment removal spells at him, which damage him for each enchantment removed, weakening him greatly. So now he attempts to flee, but I throw a damaging spell at him, killing him.
It's not just smashing buttons randomly, it does have coordination! Also Oblivion is just smashing the shit out of the attack button... perhaps sometimes throwing a power attack if you are truly bored.
Also Warhammer Online is supposed to be based around your skills too NOT YOUR AUTO-ATTACK! To be good in PvP you NEED to learn how and when to use which ability, for example interrupt the casting of a mage and then throw a damage skill, then debuffing him or stunning him and so on.
Also the type of click-to-attack system is not used for reasons like:
-Slow computers and internets are a bigger problem with such a combat system rather than with the traditional MMO combat system.
-IT can easily deterioate into mashing the hell out of the attack button.
-Dodging/blocking system can become way too easy, causing no one to die and everyone just dodging everything... unless they are zerged.
-Skills, you still need to use spells and such, which would require you to use W,A,S,D to move, attack with mouse and also hit numerical buttons to use skills and spells. This can be easy to some of you, but alot of players will have a problem with this.
-Balancing between ranged and melee classes would be even harder IMO, especially if it's aim with mouse since most people will most likely just jump out of the way constantly, rendering ranged useless.