I've been thinking for a while. It would be fitting if Blizzard had put the 3 man team, which was responsible for helping during the Founding of Durotar by stopping Daelin Proudmoore and the Kul Tiras forces; thos 3 being: Rexxar, Rokhan and of course Chen Stormstout.
Fitting, if not ironic.
We haven't seen Rexxar since Burning Crusade, but considering how well he's in relations with Thrall, it would be possible if he gets called for.
We haven't seen Rokhan since Wrath of the Lich King, except that he was briefly mentioned in the Stormrage novel; but since he's a troll and all...well, I don't think I have to explain if you completed "Horde is Family".
As for Chen, well the fact that he's already greatly involved I wouldn't be surprised if he turned up for SoO, tho he's not officially a Champion of the Horde, his involvment in protecting Durotar was certainly not small.