There seems to be more than enough 4v4, they are easily forged, negating the need for more official. Add to that the constant complaints of Certain Affinity/343's map building...
I'm going to narrow this down
In big team, these maps are possible.
Ragnarok
Exile
Vortex
Meltdown
Erosion
Ravine
Settler
Harvest
Wreckage
Daybreak
Outpost
Perdition
Removing maps that rarely come up
Ragnarok
Exile
Vortex
Meltdown
Narrow this down to what is voted for every time
Ragnarok
Exile
In short, we have two maps to play on. Four at best that even show up.