Now right off the bat yes I know modding on consoles is very iffy for any game and rife with issues. And for good reason. however, I think Halo may be in a very good spot for modded content on the console.
The way the UI seems to work is you pick a map and then it loads the map file associated with that menu item. We know this to be true with how loading mods currently works on PC. You replace the .map file and then MCC loads into the modded content. Also, the way modded weapons work is by baking them into said .map file, right? adding a custom weapon to one map does not affect any other map.
So if any modded content is baked into a specific .map. and the UI treats .map as a standalone. then could mod support be added to consoles by say downloading said .map file and then running it? this would allow modded steam users to play with console users and would remove that barrier. It would also not compromise security because if the .map files are just custom content then It’s not like it would be different to the .map files the game currently reads from.
Just a thought.