Beastly, I think, (I'm not positive), that it has been confirmed that elites will be playable in forge and custom games, where most machinimas are made anyway. Therefor, I think series like "Arby 'n The Cheif" will survive just fine.
Well, we do have to have the game fair to all levels of players. Some novice players would not be able to rank up if it was skill based, and they would not feel very strongly towards that. Maybe even lose fans. 343 is just trying to keep it fair for all audiences.