A. FOB’S should have been larger and allow you to “add on” features that allow you to defend against periodic Banished assault waves that you have to defend against by making the game somewhat like Firefight.
*examples: Turrets, hardened walls, positioning AI on the walls with Squad commands
B. Flyable Pelicans. You have to watch out for Banished Anti-Air units so in Co-op a player could help out by using a Wasp to Clear Anti-Air Turrets.
C. Banished can replenish their numbers to try and take back their own bases, they can mount search parties to hunt Chief and you can mount assaults against Banished Convoys that are trying to resupply bases. Missions to Resupply groups of marines. Mission to provide air support for ODST’s and drop of a warthog for them while you reign fire from Above. Mission to capture Sentinels or breach a Sentinal factory which you can then use their tech to modify your weapons and gear. Variety, variety, variety.
AND add more Spartans you can interact with at bases that work with you to carry out important missions. Not just the dead spartans you find along the way which was a big lwt down and kinda ham fisting storytelling. I wanna work with Blue Team, Locke, Arbiter etc and do Offworld missions such as raiding a massive banished factory or dockyard or explore MYSTERIOUS facilities like the first mission as Arbiter in Halo 2.
D. The Ability to board Banished vessels ( capital ships ) while they land to refuel or by stealing a Phantom
E. Have more Huge Crashed Banished and UNSC capital ships to explore.
F. Being able to harvest Forerunner tech from nodes in Zeta and bring them back to a Crashed UNSC cruiser to do research on via AI that can upgrade your weapons and armor. ( Make it similar to the tech trees from Starcraft ) Example: Helmet upgrade that allows you to survive and extra Headahot from Jackal Snipers etc, or explosion damage resistance or the ability to carry two equipment simultaniously etc
G. Forerunner cities. Massive forerunner cities to explore without the ( BORING ) power seeds. Similar to castles in Dark Souls. There needs to be more to do in the world along the lines of an RPG: Activating a forerunner water supply, massive lightbridges to new Large regions ( not just local ), bypassing Forerunner locks with Keys like Doom or Quake ( Doom and Quake have good gameplay ideas that Halo should use and modify ) We should be able to invade huge, complex, multilevel Forerunner cities overtaken by the Banished and have MASSIVE, sprawling battles ( think like the mines of Moria scale from lord of the ringd )
H. More Locations. Shield Worlds, other Constructs, Human Colonies, shipyards, floating vessels, other parts of Zeta. ( Warframe does this PERFECTLY and so can Halo )
I. More Labyrinthian, Dungeon like levels. Halo CE did this perfectly with the Library, Maw, the second part of Halo CE’s second level and the beginning of Assault on the control room. We should be able to explore Deep Inside the ring in forerunner factories, repair stations, subsystems, research facilities and more. There should be big underground sections to explore like the underground pipes from the real world in the matrix. VARIETY IS KEY
J. Scarabs. How were they not even in the game ?
K. More stuff From Halo Wars. More vehicles. More bases like them. More variety. Halo Wars had tons of new cool stuff. The STORY for Halo Wars 2 was WAYYYY better than Halo Infinite. No cringy scenes like Infinite did with Escharums dialogue and the mega-cringe scene where Chief has pity for Escharum after he TORTURED the pilot ( not even plasuible, sorry )
L. DUAL WIELDING. ELITES. MORE EQUIPMENT
M. Large Scale Multiplayer Battles like Battlefield. Halo Warzone was a step in the right direction and I’d love to see that return or maybe mix it up with drop pods and multiteam, flyable Pelicans and AI you can give squad commands to.
Leaving aside killing Cortana, offscreen and retconning Halo 5 you could have improved it by:
Banished warships over Zeta Halo that we see in a straight fight. The UNSC should easily beat the Banished in a conventional war. It’s like why the New Republic couldn’t beat the First Order; because the plot requires that not happen to keep the underdog tone.