To be honest, that's what I feel like the TDB map was made for (sky something? Can't remember the name). I mean the control games never end with a 20k score, it's always due to time expiring. It wouldnt make sense that bungie would intentionally make a map for 6v6 that constantly never hits the score cap. I believe it was designed for a big team style game mode that never ended up making it in the game.