There should only be 3 forge maps total with a plethora of custom options to the map itself:
Flat canvas
-Snow
-Desert
-Grass
-Rock
-Urban
-Forerunner
-Underwater
Empty space
-Halo Ring atmosphere
-Halo Ring nearby
-Gas giant
-Planet
-Star (distant)
-Star (near)
-Lonely space (just stars and nebula)
-Void (one solid color. change fog/whatever for color)
FORGE WORLD 2.0
Similar set up to Halo Reach Forge World, but bigger and better.
Lots of terrain options perfect for map remakes such as
-Blood Gulch/Coagulation
-Valhalla
-Ascension
-Relic
-Sandtrap
-Lockout
-Sanctuary
-Last Resort
-Guardian
-Zanzibar
-Snowbound
-Avalanche
-Timberland
-The Silent Cartographer (with internal configuration being a very large open forerunner interior for maps such as cold storage, construct, citadel, etc)
Basically perfectly set up for a large handful of the most iconic multiplayer maps from previous titles, while also being more than capable for new ideas.
The only pre-built structures should be the forerunner structures of the cartographer island. There should be lots of objects perfect for those forge remakes like the last resort/zanzibar fan Also… The skybox should be changeable to non-halo ring for those non-forerunner maps.
I imagine that the map would have various climates at different elevations for those major differences, and could fit together quite well. Up high in the snowy mountains and cliffs for maps like avalanche and snowbound, sunny warm beaches on the ocean where you can find Relic and the cartographer, and the middle areas where scorching deserts hold sandtrap and blood gulch