Missing maps in Match making rotation

Whats up with not including Erosion, Impact and Ravine in on the matchmaking rotation. In my opinion the pre set up maps for these maps are great for instance the Impact map the comes default with the game Relay is awesome and the one that is for erosion would make an awesome Big team slayer map. What gives with not including these maps that came shipped with the game?

I’ve been wondering this as well. Everyone complained about forge maps in matchmaking in Reach because they all had the same asthetic (grey) but these are all thematically different. You’d think they would at least have the prebuilt variant for each forge map in there.