I honestly don't think WoW looks that bad. It plays very very well on low end machines and still looks ok. I absolutely love the bright colors in WoW. It has a great since of art whether you like the game or not.
Obviously Vanguard looks better because it is a brand new game. The only thing that bugs me is how people can say that Vanguard has "no art direction and is bland". Vanguard isn't EQ2. Vanguard has a much better sense of art now. Hell, even since beta alot of the art has improved. They pretty much changed EVERYTHING. Vanguard's art is actually rather good. Not as colorful as WoW, but its not meant to be. Just like WoW isn't meant to have state of the art graphics.
I try to keep my opinions as unbiased as possible. I have played both games and think they both have their strengths/weakness's. There is no "better game". There is just a "better game for you". For me that just happens to be Vanguard.