I’ve seen ever since the announcement of Forge World, people have been demanding for larger and larger maps. This presents technical difficulties, and I personally think that the Forge maps should be smaller, similar in style to Sandbox.
Halo 4’s Forge should have one larger map akin to Forge World, and 3 others that are smaller (one Containment’s size, one the size of Timberland, and one the size of Beaver Creek). Not only does this allow for several different places to forge for a fresh experience, it allows freedom for the map due to lifted technical limitations.
A map with the same layout on two different settings could play and feel completely differently because of lighting, colors, objects, and scenery.
Finally, however, all the shipped maps need to be fully Forge-capable, but designed differently with multiplayer in mind. They also need to be independent of the campaign (a move designed to overcome the limited disc space and time restrictions).