i like the island idea and connecting maps thru skybox
for example if i make a beachside construction yard which i kinda planned to i can have a resort in construction in the background, another finished one somewhere, group of islands off in the ocean where someone has set their map too, rocket launchsite in the hills etc etc etc
id draw a plan how it looks like in my head but drawing with a mouse tired and drunk isnt the best of ideas
then every map would have a unified skybox, just a different location in it ( kinda what should be done with nucleus and frontier finale
) unified skybox is a rather unique challenge tho, if we were to have everyones maps in it it'd probably eat quite a few fps and making it look good and tropical and stuff if we go tropical fro example would require barnblitz style skybox palm tree sets customangled for each map and same island textures for everyone
also alternative story could be blu coming to the island to build resorts (and bases) not knowing that red already have built secret bases all over said island
then blu tries to get rid of red so they can build being builders league and all and red tries to get rid of blu and demolish anything they have built