Let me start with I hope dev’s see this and have thought about it.
Weapon variations, I think a huge post launch idea would to have old iterations of iconic weapons and not just have them done as skins. The simplest example is: Halo 1’s AR. To have it as it’s own weapon, named correctly as it was Ma5b would be a great idea since they have already implemented the specific name of the current AR as to just calling it AR. You could do this to every older weapon as well too. Like the older crystalline covenant sniper or Reaches beam rifle. Not to mention the addition of all the magnums as well that has had a controversial opinion of being ‘replaced’ but instead could be simply added for a different play style. I think this idea wouldn’t break the sandbox but would instead add layers to the replayability and continuations of infinite. The hard part would be finding and fine tuning the balances of each weapon, the best example would go back to the Halo 1 AR again, bigger mag & faster rate of fire but at the cost of effective range and accuracy compared with the accurate and stable current AR for infinite. I most definitely believe that there is room for these older weapons to be effectively implemented and still balanced. Possibly thruout future battle passes as well.
Just for consideration
I very much disagree. It will absolutely dilute and break the sandbox. But I’m sure they will still do it because it’s an easy way to sell “new” DLC and seemingly keep the game fresh.