Im to the point i would rather updated race models than a new xpac.
I really want a better quality artwork for all the old races, I'm TIRED of seeing nothing but belfs. Between the utility of an AOE silence that steals mana and the better looking and small characters, most raiders and a huge chunk of pvpers play BELFs.
I'd specifically like to see:
Undead (best animations ingame, imo) - Armor not pierced by bones (Knees, toes, elbows, hips, spine... seriously, do I buy tabards and take scissors to them immediately? At least give us a checkbox to have this turned on/off.) More hair options.
Tauren - Better hair (head and body), better faces (check Taunka for ideas!), updated hands (please!).
Trolls - Males need the option for upright posture. Females need the option to crouch. Even if these were just idling options, it'd be nice.
Orc - Females really need some better faces. Males need the ability to stand upright now. They haven't been slaves in ages, after all.
All races -
Some marginal resizing options for all races so there are variances in musculature, fitness and height within a set spectrum of the given race (so the tallest gnome will never be taller than the shortest tauren).
All that said, I don't expect to see changes. Of course, I was one of those players hoping that druids would get regional tree forms with Cata and instead druids had treeform virtually taken away and when druids are in treeform, it's a horror show.