Firstly, to have shortswords instead of longsword bombers, as their described as being used as precision bombing runs.
Secondly, maybe give the UNSC the ability to research a tech that unlocks SPARTAN-I,II and III that mite repel boarding parties or at least have a bigger impact in the game, as their one of the most iconic halo things.
Next, you could have artifacts that mite give you an ancient forerunner ship or vessel or maybe open up a wormhole or something similar.
You could also add a covenant capital ship that kind of is like a mini high charity that acts as a mobile repair station.
Lastly, you could add certain abilities to covenant capital ships like deplorable scarab or cleansing beam to take planets quickly and the UNSC could get Spartan assault squads or sparrowhawks to increase their assault effectiveness.
Maybe, if possible, add the ability to name frigates so they can be called like Forward Unto Down or In Amber Clad.
Another thing, I was wondering if there were going to be prowler class ships or stealth ships with some sort of detection ability, stealth advantage or mine laying like the Point of No Return. I know there's the Oni sloop but that's more recon focused which is why i was wondering about a stealth ship.