I am finding that a lot of the setting development I work on focuses on just how far I am willing to allow the brain to be exploited. As I stated earlier, TDE is a pre-singularity setting. AIs are (mostly) nonexistent, and non-destructive uploads of cerebral activity is likewise limited to GM fiat. Thus, one of the defining aspects of technology is just how far technology will go in allowing the brain/digital interface.
For Saturn, their Moreau shock troopers are similarly limited around the need for a "normally" developed brain. Since they cant just upload memories and training into a brain, it has to be grown - and in a form radically different than the human body, the Suturnines discovered that implanting the brain and allowing it to grow with the body is the best way to get a combat effective soldier. Even then - even after having a human-origin brain grow organically in a non-human body - there are... complications.
Brain transplants are possible. I figure they are a very common occurrence- and in some quarters, a booming business. A vat grown brain, raised and trained, can be useful in some circumstances - especially if trained with AR - but it will still be limited
Information in the brain is stored chemically as well as electrically, so complete replication of a psyche is impossible. Further, the sheer amount of data in an active brain is enormous - and in TDE, downloading all that information stretches the limits of most data storage devices. Because the science in TDE has an incomplete understanding of the brain, attempts at uploading the brain (even with chemical augmentation must upload all of the data in the brain - neuroengineers simply don't know which information in the brain is necessary and which isn't - so they have to try to capture it all.
With the brain, there just aren't many shortcuts.
One other plot element I want to introduce is "cemetery ships." These will be a development of one of the Hegemons with a large space presence -- ships that are loaded with thousands of vat grown and artificially trained disembodied human brains. The ship is stuffed to the gills with these brains that are linked in to a series of teleoperation systems. The other thing on the ship? Guided missiles and drones.
Instant 'zombie' spaceforce.
How bad would it suck to be one of those brains? Bad enough a terrorist / freedom fighting organization has sprung up with the intention of sabotaging the use and production of the "drone-zombies."
Next up? Militant neo-zionists with the closest thing to stealth spaceships. Yeah, I am going there.