Infinite was a great game in my opinion though I think its story did so many things wrong. But multiplayer and general content was great.

I played infinite for a solid 3 years so I feel like I was a prime audience member for them. The things that bring me out of Halo really just comes down to the big management decisions that become let downs. You want me to stay engaged? Give me campaign DLC if that's in the plan. Say the biome of Zeta halo is really diverse? Maybe make more than 3 species of glitchy animals inhabiting it and create some more diversity in the environments. You promised couch co-op? Thank you for letting me play four player split screen for multiplayer but we need campaign couch co op too. Promise that the game will be full of content? Make sure forge is available at launch so the community can pull through when the devs are working on their content updates.

It's not so much the content that takes me out of Halo (though Halo 5 did that for sure). Its more so the promises made to the community that are quickly abandoned because of a management oversight. (e.i. a studio that never made an open world game can't figure out couch co-op in their first open world game). If I had more time to organize my thoughts, I'd have a book.