This is something they need to bring back since the beta weapons are already reasonably balanced they can use those in the competitive playlist and have that as 4v4 slayer+objectives. Also if Elites do come back as playable then it can be like Reach where the had Elite slayer as an option.
In Social playlist, that will have the standard slayer, BTB, infection ect and you could be Spartan and Elite instead forced one or the other. And in the social playlist, they could add a couple of unbalanced weapons (1-3) and have a forum specifically made for the community to suggest what needs changing on the unbalanced weapons. Which in turn could later be added to the competitive playlist.