You can do a number of things with model swapping/changing. From making priest gear (or any target that needs to get dropped fast in PvP) a bright pink to enlarging the WSG flag so it can never really hide from you.
You could also change the tauren model to something less... large and obtrusive. This works wonders in tight instances like Scarlet Monastary or the tunnels in WSG or Towers in Alterac Valley.
You can view/extract models with
this program and learn to use it by reading this handy
guide.