In short: everything you earn, find, and upgrade will carry over, but abilities and upgrades that only become available through story progression will only carry over once that point in the story has been reached. This will be balanced out by making the game tougher.
In detail:
NG+, playing a game a second time with your unlocks and upgrades carrying over, is something a lot of games have. FO doesn't, unfortunately.
Part of the reasoning behind that, according to the game's director, is that it would break the story related progression of your character.
Which is true, in part, but I'd like to present an option how this could work. This is just in regards to your skill tree abilities and upgrades, plus upgrade collectibles.
In general, there are abilities on your skill tree tied to different force Powers or equipment (i.e. dual bladed saber) and general upgrades (like more force, more health etc.). The force Powers have subsequent upgrades (for example a stronger push, a stronger pull etc.) and once you unlock the base ability, other upgrades become available, some immediately, some only after you aquire another ability through story progression.
What I propose is to maintain the way certain abilities are only unlocked by performing specific actions in the game, through story progression, but once those abilities are unlocked and in turn unlock connecting skills, your unlocks from the previous playthrough carry over - plus the upgrades you got from secrets (which you would be able to collect a second time to gain their upgrades again and become more powerful).
This would have to balanced out by an increase in game difficulty, most likely enemy health and damage taken, plus, I would hope, new and different enemy group composition (like adding additional enemies or a tougher enemy into the mix).
How would that work, specifically?
Let's say your first playthrough was pretty complete, you gained enough XP to unlock the complete skill tree and found all the secrets to increase health and force, and BD's stims.
When you start the game (once combat starts on Brakka), these things will carry over and will already be unlocked:
All general abilities available at that point in the story (more health, more force, etc.)
All combat abilities available at that point in the story
All force power upgrades available at that point in the story (meaning Force slow AND its upgrades)
The additional benefits from secrets found that increase your health and force.
And possibly the Light Saber damage increase.
This last one should be discussed, though, as this was also tied to story progression.
Since you have Force Slow and unlocked it's it's upgrades in the first playthrough, as soon as Force slow is available to you, all your unlocks carry over and you have all the upgrades for it immediately unlocked.
And this continues in the same way.
Once you get BD-1 and the ability to heal, you get all the Skill tree upgrades connected to him that you've unlocked in the first playthrough (more health from stim packs, force reload through stim packs) and the additional stim packs you found through secrets.
Once you get push and pull, all the upgrades and connected skills available at that point in the story that you unlocked the first time around will immediately become available.
Once you get the dual blades, those skills become available.
Once you get double jump... you can double jump. Not before.
The unlocking of abilities through story progression stays exactly the same. All that changes is that once unlocked, you will.get.immediate access to all upgrades you unlocked in your first playthrough that are now available.
But it wouldn't make sense to have BD-1 and healing on the Brakka train, or the dual.bladed lightsaber early in the game etc., so that way that won't happen.
Of course, that will still make you a lot.more powerful more quickly, so this really would have to be balanced out somehow with more and/or tougher and more aggressive enemies.
A few of these points, specifically the health increase through secrets and the increase in stim packs being carried over and able.to be unlocked again and thus adding up, should be discussed, though, to not make things too easy.
God of War has a similar, albeit much more complex, NG+ System, but this would be much more like the system in the Batman Arkham games, which are pretty much my gold standard for NG+ along with the Souls games.
Of course, none of this is easy to do or quick, but I think it could work. In fact, this could work for NG++ and so on as well.
Let me know what you think.
Thanks for reading.
