Personally, I would like the option of a customizable backdrop on plain maps like Tidal or barrens in H5. Not just changing the color of the backdrop I want to change the full thing like make it instead of a forest backdrop it’s a New Mombasa or New Alexandria/ city type view or make it into a complete starry night abyss… do you agree?
What are your thoughts or ideas?
Every asset ever that the game has. Not just some blocks, at least a bit more than that.
Single Campaign mission makers, failing that making your own fire fight maps and such.
Don’t forget how awesome halo online’s forge was as well as halo 5’s.
environmental changes, such as rain or snow and environmental sounds, such as birds or the sound of the wind
A.I. for epic battles 
Dynamic player shadows on forged/placed light sources.
Explanation: Let’s say you run in front of a light in forge. Your character of course glows from the light but there is no shadow caused by your presence. With dynamic shadows, if you run between a wall and a light, you will see your shadow on the wall opposite from the light.
I would love to see an option to have lights placed in forge cast player shadows at a variety of ranges (from small lights with brief shadows to strong lights with long shadows from across the room.) It would likely be limited or on a tight budget to save on performance, but just having the option would be great for that much more immersion and detail especially in indoor maps.
I would also love to see the Pelican and Phantom as fully drive-able vehicles without needing to use an invisible miscellaneous vehicle.
AI for sure. If they only improve Forge in one way, this needs to be it. I would love to play a bunch of custom campaign maps, or make my own giant battles.
Giant piggy