My theoretical Battlefield game would also take us back in time to the style of game that Battlefield 2 was. Battlefield 2 had two amazing features I have missed in every Battlefield game I've played since: commanders and replay.
Battlefield 2 allowed a single player to take on the role of commander and instead of going pew-pew around the battlefield that player had a top-down view directing squads of players to objectives and calling in artillery strikes on areas. The enhancement I'd make to bring this feature back would be a ranking system for commanders that way its not just luck of the draw on who gets to take on this key role. Yes, this would gate keep some players but I think its one of those key roles that could make this sort of game that much better.
Battlefield 2 also had a replay system whereby you could go back and replay the entire match. Many games have this system to a degree, but Battlefield 2 is the only Battlefield I am aware of that has had it. I spent hours replaying matches, watching epic fights, rewinding them, re-watching them from different angles, and then capturing epic combat footage. I made a good number of videos (which sadly were lost to the now defunct Google Video platform that Google had before they acquired YouTube).
Yes, we live in a world of streaming and super simple video capture, but a replay system allows for so much more than just what a single player's view was. With the content creation tools that exist today a replay system would be an amazing capability and I have no doubt would result in some epic community created content.
I also think graphics engines are at a point where you could use a current state engine for years without a concern about it looking "old" in a couple. This would be a key element to making Battlefield-as-a-service.
Of course I mentioned battle pass and I understand that may tilt some players, but I think its the reality of the current market for these types of games. If it was combined with new maps, weapons, and campaign settings it would be almost no different than buying "Battlefield version 2022/2023/2024/2025" and the improvement is that your investment per pass is building on all previous passes. Compared to when I started playing Battlefield 3 it didn't matter what I had accomplished in Battlefield 2. Ideally a battle pass would focus on cosmetic and "battle medals" type awards and not any power increases (i.e. don't tie unlocking access to a weapon behind battle pass).
If this game were made I'd play it. Would you? If so, leave a comment. If not, believe it or not, still leave a comment.