The best part of halo infinite were the marines and how they actually help you against enemy ai. It wasnt perfect but the proof of a fun conccept is there. I could imagine a campaign where you start off with just a few ai that follow you and by the end, you have a smalll army. This isnt an original idea, another game called freedom fighters has similar gameplay so I already know its fun and works. All it needs is simple commands for ai. freedom fighters has a very simple system with just 3 commands to control your ai.
As you progress through the game, the battles get bigger and bigger. the combat and strategy evolves as you gain more friendly ai and fight larger battles. You start as a lone wollf like any other shooter and slowly learn how to command a team. this kind of evolving gameplay also lends itself well to cool stories where you need to build a resistance to fight the big bad,
Players were able to abuse the campaign difficulty with marines which to me, tells me it wasnt thought out that well because the game tries to let you beat it with or without ai. It needs to pick one or the other. I like how the open world has friendly ai and the linear levels is just you. However the linear levels could have been done better.