I feel like it would be cool if after completing the game we could unlock a more traditional mission select menu and just play through the campaign like with previous titles. (also mission replayability would be nice) I love the open map idea but for future playthoughs I might just want to focus on the story side of things and not have to go out finding armor cores/etc. In terms of upgrades those could be based on difficulty level or just let us pick at the beginning of each mission or something. (we already beat the game afterall)
In terms of the campaign where it currently stands, on top of the ability to replay missions (should’ve been a no brainer imo) I really think it should be made clear that once you begin certain missions you can not return to the open map until after completing the entire campaign. My complete wish list on this would be that we can return to the open map between every mission, but at least tell me there’s no turning back at those points. I’ve heard it said that it feels like 343 had 2 games and just slapped them together and that makes sense as the pacing does feel strange to me. Not sure how useful this is cause the game is already out but it would be a nice quality update for whenever I decide to replay in a couple years. hopefully future DLC can also have something like this.
I hope this came off as constructive.