Battle For Zeta Halo DLC

Alright, you know new Mombasa? of course you do it’s one of the most important events in halo 2 so i was thinking imagine an semi open world dlc where you and your squad of odst have to defend points or larger UNSC bases that you might find in the main campaign before they’ve been destroyed sorta like halo reach but it would have a great focus on your actions changing the story im thinking being able to control platoons of marines from one of those hologram tables you see in halo 4 and where you send the marines could impact how and when the campaign ends now how would the campaign end? well im thinking if there’s a day night cycle lets say every 3 days the banished gain around 4 squads while the UNSC forces would be stuck at around 3 platoons (4 squads in each platoon) and the longer the campaign goes on the more you have to thin your forces before eventually holding out at whatever base is the last to stand. now this is more of a open world then usual which is why i think if we get this in any form it would be in a spin off game but how would y’all like it or what would you change