Here is a small update on this, an answer to a question that was asked in the most recent Developer Chat on Twitter:
http://forums.wow-europe.com/thread.html?topicId=14129945695&sid=1
Q u o t e:
Q: Still no word on updated player models for classic races makes me angry. 3 expansions with not a single update on it.
A. We definitely want to do it. Our artists would love to - believe me. The worgen and goblin took an enormous amount of art and animation time for Cataclysm. It's definitely on the list though. We recognize the problem with old models in shiny new armor.
You may have noticed that this update didn't exactly provide an ETA, because as you may imagine, a lot of time and work is required to update all the old models. It is on the to-do list however, which should hopefully come as welcome news to most of you