I think Forge should come back in Halo 4, but it should be a Computer Program that allows you to fully create the geometry, structure, and layout of the map. Then place exact weapon/object placements without fiddling with your thumbsticks/coordinates, and without the game engine creating issues such as drag.
It aught to allow you to skin every line/surface you create from a well of categorized skins that appear in the game, spawn sounds from categorized sound pools, and spawn gadgets such as water sources, as well as creating “dedicated zones” with separate water levels. You can also change the lighting of any sector you create, and define properties such as texture opacity to create custom windows/interesting barriers. As well as applying “fog/effects” to sectors to change hue, coloring, and maybe even create backwash/esque sight hindering and weather effects.
Once your map is finished, you can transfer it into Halo Reach via your file share.
This concept is inspired heavily by a program I used to create/edit maps in Doom II called Doom Builder (look it up if curious).
You had the slightly limited ability to create nearly ANYTHING. Even manipulating the game engine to create multiple stories that exist in the same vertical space, which was physically impossible in vanilla Doom 1 and 2.
Possibilities were limited almost entirely by imagination.
Now unlike Doom Builder you wouldn’t necessarily be able to input your OWN textures/skins/sound/objects. But that’s simply because the Doom Community over the years is… trustworthy. The Halo community is still vast and immaturity still flourishes.
But even then I’d certainly say having access to ALL THE RESOURCES IN THE GAME to create your maps, and being able to shape those resources in any way you see fit is alot better than a limited selection of objects/effects.
You may even be able to unput scripted events! Doom Builder had this function. Fully functional doors, switches, traps, earthquakes, map-changing happenings, elevators, treadmills etc. Anything you want to be interactive is possible.
Not only that, If handled properly, I think this program COULD theoretically be a small, easy to install/low PC requirement program, that pulls all it’s resources from an online server. Basically, in order to Forge you will need little more than a crappy computer and the internet. Both of which you will need to transfer your map through File Share anyway. And I’m sure even casual forgers will find this system much easier to work with than Forge. Especially if their imaginations are still limited to the small things that can be made in forge. Which hopefully this major improvement to freedom would… expand.