I am vey familiar with all the actors aside from Paula Patton. If I had to guess who was playing who;
Ben Foster is almost certainly going to be Anduin Lothar.
I have a feeling Travis Fimmel is going to be Durotan.
Toby Kebbel. I think he may be playing Medivh.
Paula Patton I don't know, but Garona seems to be the only female of note. Or Draka.
Rob Kazinsky is another difficult one. I've never seen him play anything but a villain. Even in Eastenders. He's not how I'd imagine Blackhand, so I have to go with Gul'dan.
Dominic Cooper I can only see playing Khadgar. He always seems young, however old he gets.