Which class has the highest Skill Cap in Vanilla?
Very often when there is a discussion about skill cap in Vanilla WoW people falsely say that (Undead) Rogues and Mages have a low skill cap because they don’t know what skill cap / ceiling actually is. In order to understand the concept you need to know the difference between skill cap and skill floor:
A skill cap is what a class can do when it is being played to its fullest potential.
A skill floor is the minimum skill required for a class to succeed.
In patch 1.12.1, both Mage and Rogue have strong cooldown abilities (Blind, Preparation, Coldsnap), and with spamming them you have easy edge versus many classes. This means that both Mage and Rogue have low skill floor to begin with, and even bad players can manage 1v1 PvP just fine with these classes.
However, when it comes to skill cap – a skillcapped player can use those “overpowered” abilities way further than normal players.
Lets say you are in a 1v2 situation: You vs a Warlock and a Priest
As a Mage or a Rogue, you have abilities to CC both of the enemies. You have the ability to lock a spellschool of the target. You have defensive abilities to escape their CC.
As a (Retribution) Paladin, you only have 2 weak interrupts and no proper crowd control.
A skillcapped player as Mage or Rogue can easily outplay an average Warlock and Priest, because Rogues and Mages wider range of abilities to use. If the same player was playing a Paladin, he would most likely lose because of the limited amount of abilities on the Paladin class. This means that the Paladin class has lower skillcap.
It is far easier to play a Retribution Paladin skillcapped than it is to play a Mage, even the entry skill floor for the mage might be lower (bad player can manage on Mage just fine but get shat on as a Paladin).
In my opinion it is impossible to say that which class has the absolutely highest skill cap in Vanilla WoW. My personal opinion is that due to the fact that many Rogue abilities do not have a Global Cooldown, they have the highest skill cap. However it is very situational and everything changes if you consider group play. For solo play I would rank the classes like this:
High Skill Cap: Rogues, Mages
Mid Skill Cap: Warlocks, Hunters
Low Skill Cap: Priests, Warriors, Druids, Paladins, Shamans
In Group PvP the list comes obsolete as so many factors come to play. Especially healing classes have way higher skill cap in group play.