I'm calling it now: It's Medivh.

Some people think that wouldn't be a good movie, since the significance of Medivh's character isn't explained very well in World of Warcraft, but I think they could actually use that to their advantage. Remember, the Warcraft movie is coming out in March of 2016 and features Medivh as one of the main characters. One of the problems with the Warcraft movie is that it takes place waaaay behind where the current WoW storyline is. The Warcraft movie takes place before and during Warcraft: Orcs and Humans. Since that game came out, there have been two more RTS games (each with an expansion pack) and an MMO with 5 expansion packs. At this point, Warcraft 1's storyline is a relic of the past, and I'd bet that a lot of current WoW players don't really know much about its storyline. Wouldn't it be convenient if Blizzard had something in WoW that directed the players' attention back to the events of Warcraft 1 (and specifically the events that will be covered in the movie)? And given the pacing of the expansion pack, isn't it likely that we'll see the conclusion of the legendary quest just a few months before the Warcraft movie comes out? The timing is too perfect to ignore.

The fact that a lot of players have no idea who Medivh is would actually be a huge advantage. When they make the dramatic reveal that Khadgar is not who he appears to be, players who aren't familiar with Warcraft 1 are going to feel left in the dark. Obviously they'll realize that this "Medivh" character that's being dramatically revealed is someone of significance to the series, and since they're already invested in the legendary quest's storyline, they're going to be intrigued. From there, they can either reveal Medivh's past and leave the players interested in seeing the movie adaptation, or they can be more vague and leave them without the full picture, which will drive them to seek out more information. Either way, bringing Medivh back would be the perfect way to tie WoD into the movie.