I do remember this issue/suggestion was brought out both here and on ModDB as well, if I'm not wrong. However, I couldn't really tell you if the removal of those sounds was due to technical reasons or not.
Now that we dealt with this aspect, should the proposal still be valid, what if we widened it in search of more
differentiation and
uniqueness. Quite recurrent words these days by the way, aren't they?
In brief words, just to put flesh on the bones of this suggestion: what if each faction had its own defeat and victory lines, belonging to the very leader of the faction (or one very prominent hero). For example, Gandalf will speak words of sorrow or jubilee for Gondor, Théoden (and Éomer too?) for Rohan, Thorin for the Dwarves, Sauron/the Witch-king for Mordor, Saruman for Isengard, Galadriel for Lothlórien (and maybe Thranduil for Mirkwood as well) and so on. What would you say about it? We could arrange here for collecting suitable lines from LOTR and the Hobbit.
P.S. Smaug or Azog for the Misty Mountains? That would surely be really interesting to experience