I agree with the most common wishlist items that others have already mentioned, so I'd like to mention some personal wishes not mentioned:
- I'd really love to see all the Halo alien species represented in the game again, especially those that we haven't seen for a while, or at all from 343. I know this runs the risk of undesirable redesigns/interpretations and errors, but I miss the variety and charms each species brought to the table, whether through gameplay or story elements and cutscenes.
It's obvious that with where Halo 5 left off, and Cortana's direct warning message to most of the sapient species of the Galaxy, that this event is affecting everyone and I would love to see how each species is reacting to it and who might come together to join forces to fight against it.
I've always loved the Covenant side of things, and especially enjoy the idea of more cooperation between the species and how it would allow us to see more than just the Human side of things. I understand if not all species can make it into the game, but it also feels like lost potential and a waste to not at least involve those species that held so much influence in the war and past events such as the San'Shyuum, Jiralhanae, and obviously the Sangheili, and we've seen through extended lore that there are individuals from each of those species who are willing to work together peacefully aside from the Arbiter.
Having each species represented also offers the opportunity for them to make an appearance in a Fire Fight mode, or (while this is a personal niche of mine) the opportunity to have more playable species similarly to how Gears of War or Doom allowed for people to play as multiple species. I doubt anything like that would happen, especially when just getting playable Elites back on the table has been a struggle, but it's still a neat feature that has come to mind over the years. The idea of playing as a Grunt or a Hunter has a lot of appeal to me.
Other than that:
- I'd also enjoy the option to fully customize my Spartan, as in a character creation option, though I guess that option depends on what kind of campaign and game modes we get.
If we have something similar to Reach where we can play as our own Spartan in the campaign, or if we had alternate modes like Spartan OPs, Firefight, or even something entirely new to follow the current trends of other games and making these "Live Services", then I'd at least like the ability to create an actual character (customize a face, hair, and all that good stuff).
We've had somewhat similar, yet "scattered" options throughout the Halo games (playable characters in ODST Firefight with or without helmets on and multiple voice options in Reach) so it's not a stretch to bring those all together to create a new, and in my opinion, enjoyable option of having our own personal Spartan, even if we only ever see the face in a hub like setting or cutscenes.