I wouldn't use "inequality" in the sense that someone is "better" than someone else. I think what the game needs is the ability to be different, to develop a character in a unique way. WoW has grown to be incredibly shallow and strictly controlled arcade experience rather than a deep MMORPG. Everyone must do the quick on-the-rails questing to max level, and then they must raid the same instance at the same time, no exceptions. The only thing you get to "choose" is how many different difficulty modes you want to grind the same content.
What the game lacks is the ability to make real choices that affect how your character develops. You should be able to choose to do 5-mans as your end-game rather than the large group raids, and they should provide a meaningful and challenging experience (e.g., lvl60 dungeons, TBC heroics). You should be able to choose to focus on professions and gold making as your primary focus, and get unique and powerful rewards based on your skill and dedication in it. You should be able to choose to schedule a few nights per week to play with a steady raid group, and be rewarded for it via progression into content you wouldn't otherwise see. You should be able to choose to play a certain niche role to specialize in, and fill a unique role in the game/raids/groups. You should be able to choose to focus exclusively on your main and get unique benefits/power over someone that chooses to develop a number of alts.