ATM there is no slayer for this game type, what so ever. So at some point will this be added, because as it stands there are only objective game types in it.
Hence the name “Throwback” only objectiv. I did stay up for some snipers, but i guess Spartan Ops will do, Oh wait they havent released episode 3 yet… FML
EDIT: feels like i should explain a little. I suppose you may not have been playing Halo 3 that much, there was a playlist called Team Throwback and it to only had objectiv gametypes, there may have been in H2 too, but i dont care, never played it.