Hmmmm... if it's a fossil.... that wouldn't make sense, the warm climate in Tanaris and Stranglethorn coupled with the ample supply of bio-breaking bacteria would have demolished the bones long ago. It must be fresh, or at least only a few years old. Creepy to think about.
As I commented in another thread that showed an even BIGGER one found off the coast of Dragonblight (which looks much more fossil-like, and given the sub-zero temperatures of the water, very likely is) it is probably just Blizzageration feeding on the
Rule of Cool and not actually a creature viable to appear in the game. The biggest limitation would be the size: something that big will be very confusing to fight against, as it would be hard to know who it's attacking and, possibly, lead to its model cramming against the player's, making it difficult to select your own character.
I do think they're nice decoration, though, for that spine-tingling "what if these things are real" feeling. This thread is proof of it.