Dawn of War 2 did this well, each race you played had an accompanying announcer and I think that's enough for EC. 1 per race, themed obviously. EC could also do what Dota 2 does, and that's have additional announcers unlock as part of the micro transaction marketplace. You can also share the announcers you unlock with your team in game. I would definitely play to have Neroth, Eliphas, Kyras, Angelos, The Grot, <insert character here> from DOW2 tell me what's going on.

Planetside 2 has different announcers for each faction but good lord they're bland and their vocabulary is extremely limited.

Skip to 1:45 in this video:
View: http://www.youtube.com/watch?v=etm3Z8E4F18

argh... now I see the actors everytime I play the game and the models shout something! damn you for linking funny things for us