I have no idea why it should be halo style (I don't even know how it is in halo), but I can assure you that there will be a good skill based ranking system, maybe Elo-rating like in supreme commander. Elo however, while being very accurate in measuring skill, has the motivational problem for more casual gamers that you start with an average rating and lose as much points as you win vs an equal rated opponent from the first game on, while almost everyone can climb to level 20 or 25 in warcraft III for example.
Maybe it would be a good idea for the ladder to have something like in Warcraft III with regular seasons and ladder resets while additionally having a persistent elo score for every player and match making being mainly but not solely influenced by the elo score.
another thing they should think of is having a separate from the ladder tournament series system like they have in Tennis.