It was NOT inspired by WoW (or guildwars) that is the point. I made a post #58 where I linked to a video from last year where the 2 lead designers stating that this was not the case.
I also linked to a reddit post where I explain in detail why the mechanics are nothing like a WoW if you look closer than just "oh it can only be used after each X". The similarities are only on a really supericial level.
4E was inspired by Soccer, Magic the Gathering (and other trading card games), and wargames (like chainmail). It was verry much made for play in person with physical props (thats why the powers are made for cards. Even the at will daily and encounter structure works best with cards to track it).
Similar your example with powers is wrong and it feels like you never tried to understand the 4E class differences different. Have you ever played Magic the Gathering or a trading card game? Because there also all 5 colours have access to the same "features" (same card types, and same rules and in theory same mechanics). There is also an overlap in cards between colours.
Still it is one of the best designed games and is known for making the colours (and even 2 colour combinations) be really different thanks to their colour pie. And this is a reason almost all modern games copy Magic the Gathering.
Similar to Magic the gathering there is a base which all classes can do. This is deal damage (and in Magic it is having creatures). However there are things which not all colours have access to. Blue has counters and card draw and hard to block creatures. Green also has some card draw, but big creatures and creature enhancements and normally no counters. (There are some specific exceptions but thats too complicated for now). White also has some hard to block creatures (flying, but no unblockable), but is more specialized in having better small creatures. It can only draw single cards. And it can also increase power of creatures, but more wide (several creatures) instead of focused like green.
Similar in D&D 4E different classes had access to different effects. Rogue are specialized in just dealing lot of damage, mostly single target, but as high damage as their main goal they also have some "square" attacks. A fighter on the other side will not just have a damage square attack. And especially not with 2d6. Thats the big difference between weapon attacks and spells in 4E. Spells have fixed damage. Weapon attacks scale with the weapon size and take their properties, weapon attacks might even REQUIRE a specific weapon. While spells dont require speciic implements. (There is a wizard class feature to specialize in a certain implement, but its not specific spells)
Both a wizard and a fighter can deal damage to an enemy and slow them, but for different reasons and in different ways. A fighter can slow enemies standing next to them. To make them not get away from the fighter. The goal is "attack me!"
Wizards can slow enemies at range (several ones at once). They do this to make enemies need more turns to reach the allies at all. So its goal is "Dont attack"
And even with overlap, each (non simplified) class has some really unique abilities. Some of which became really iconic. In 5E a sorcerer has no single unique spell.
