Wow, both past and present, has its assortment of bad guys, some with long standing lore, others with very short.
Lets talk about given everything that has happened in the story, and so many villains who have parted world of warcrafts story, who do you feel has had the best story, the best development, the best send off, and overall the best impact on the overall wow genre.
this isn't a vote for who is most powerful, its who is overall the better villain.