Ok i just saw that screenshot ( the second one in the light column (the pit-lord)
http://www.worldofwarcraft.com/insider/07/anatomy.html And im wondering if u are revamping the textures for the expension ?? or is it just made like that to look better for show-off ?? thx :)
No, that picture is of a render, not of an in-game model. That level of detail would not only require (at the very least) a major rendering engine upgrade (if not an overhaul), but a system requirement boost that would likely require hardware that has yet to be released.
Oh, but to otherwise answer your question, there will be slight increases in the texture and polygon detail for items and creatures moving forward, but nothing that dramatic.