The eyebrows are way to light for that hair color, I think they are to way light in general. The eyes are also much lighter than they should be, the Diablo III Wizard has dark brown eyes rather than dull gray eyes. The shading on the face could use some work to, right now it looks meh.
From the screenshots it looks like there are minimal differences between this model and the watcher, Mostly that both shoulders are the same size, and the hair has been completely changed. If you are going to change the hair you should do it so it matches the wizard, at least as far as the bangs are concerned. Right now the transition between the hair and forehead are really awkward, you need to either have her hair coming out above her forehead as if it were pulled back or have her forehead covered with bangs in the transition. Considering you have the hair-flaps hanging off of the side of her head I'd go with covering the transition with bangs.
The chest wrap could be better, the details there are very stretched and the wrapping is sudden and abrupt were her boobs are. The shoulders are incredibly blurry, which is a big minus because they show up in the portrait animation (at least for the watcher).
-Edit-
Is her skin supposed to be showing at the top of her boots? Because right now it is really shiny, and looks metallic. If it is supposed to be skin tone it down a bit.
Why is the skin path for a custom model overriding a default texture? You should set the skin path to something like DiabloIIIWizard.blp rather than replacing the sentry's skin :/
Also, with the team color possibilities of this skin team color should have been incorporated somewhere, add team color!
Anyways, Re-do the face + fix the shoulder/chest wrap. This model/skin combo looks like it has a lot of potential, but right now its lacking :/
Hope this helps on how you can make it better
