I think I tried WOW once when it had a free weekend so I can't really say much one way or another. I simply don't think it's a bad thing to say something was influenced by other games, even if it was just using what had become standard terminology. Even video games. As far as 4 I don't really care much one way or another, I bounced off of it but others enjoyed it so viva la difference.
I loved WoW. I have 5000 hours played on WoW. I think ALL of OSR and 5E clones would became better if it would be more like (original) WoW.
The problem is that this "4E is like WoW" was used by people to make fun of it (and still is) and that it is NOT AT ALL TRUE and mostly just shows that the people saying that have a lack of understanding of gamedesign.
As a comparison. I like steak, and I like the new Haribo Gummi bears. Now if vegans would make fun of gummi bears just trying to immitate steak and thus sucks, I would still feel annoyed, even though I like steak.
4E is inspired by many games. Even some great games like magic the gathering. And I think the open inspiration by other games is what makes it better than every other edition of D&D by far, because it uses more modern game design overall and less outdated stuff. WoW or MMOs are just not games it is inspired by.
- Magic the gathering is a clear inspiration. It has the same rules wordings. Similar layout and ways to use keywords /types and has almost 1 to 1 the golden rule of Magic the gathering in its own rules. This is a game made by WotC as well.
- The at will, encounter and daily abilities, are made to be extremly easy to track with cards. They even sold cards and made it possible to print cards from character builder
- Soccer (and or trading card game based on soccer). It tries to have similar teamwork. Thats why it roles are named after soccer (defender, leader, striker). And the famous marking mechanic is 1 to 1 taken from soccer. The lead designer worked on a soccer trading card game before.
- Feng Shui RPG: It uses the same minion mechanic. And also feels a bit like an action movie. The lead designer worked on this rpg before
- Wargames like chainmail etc.. It uses the same grid, same non-euclidian movement as several wargames (like bloodbowl). It is also fully embracing the grid, having tactical positioning and movement as its key features. The lead designer worked on chainmail.
- It of course also is heavily influenced by prior editions of D&D. On what the designers worked on.
I just cant find mechanics inspired really by how WoW plays. On the other hand I can find A LOT of D&D inspiration in WoW. (Classes, races, spell names, etc.)
So to make another comparison. Saying D&D 4E is inspired by WoW is like saying "the Lord of the Ring movies are just Harry Potter clones."
My favorite part of that is how they say "oh there were many good game designers in 4E like X and Y oh and Z and whe should not forget W..." and no Mike was mentioned.