The cancelled version looked STERIL.
Diablo 2's look was a prebaked background, colorfest in fights (yes, even purple

), and a very specific style of armors, weapons.
In the cited "it looks as wow" picture, we got many elements which people associate with "WoW", but in reality, they can associate it with modern, non-realistic game design as well.
One can argue that the "curvy" rooftop of the building MIGHT look like something from WoW, but as the cited screenshot obviously shows, (and which is clear to anyone who actually played WoW and seen some different architectures there), it is a style which are used for Night Elf, Troll, Human, sometimes Orc, and Dwarven "wood-based" stuff - it has nothing to do with a particular style, it is just not a photoshoot of a building roof automatically turned into a pre-rendered background. That is it.
Well, let us look for more "WoW"-esque elements! There is the weapon and armor rack. One can immediately recognize some of the classic Diablo 2 breastplates and helmets, as well as the correctly rendered, not too huge, properly modeled weapons, with some unique traits. Another thing D3 does not share with WoW, as again, to anyone who played Wow, it is clear, that weapon-wise, Blizzard can create a lot of crazy stuff with overblown proportions compared to its wielder.
Now the colors, we might start arguing, but then again: WoW's STYLE is that every different enviroment has a different style. Different colors and lightning in Zangaramars, different feeling in Uldum and in Vashj'Ir, totally non-human feel in Netherstorm, and a more casual "human-esque" feel in Elwynn Forest - not to mention the dark-fantasy journeys at Icecrown or some very exotic places in WoW overall.
So yep: D3 has colors, has some "muddy" feel when it comes to the background also, and damn, it has light sources with some bloom in them. That is WoW? Or that is just a frequently used effect? Shoulderpads, they are the last ones left. They were visibly large in D2, obviously, and they might have grown a bit in size - but they are nowhere near in size of WoW's huge, again stylistic and "too large" shoulders.
That is what I am seeing. I might need glasses. After all, I AM wearing glasses, have been playing D2 and D1 in the last decade, as well as playing WoW since 2006. Blind me.