>>5246654I do ponder if there is a need for fusing vs just full scale cybernetic implants that makes even Iron Hands blush if they had any cheeks to blush.
Most of the novels I've read seem to say that bionics are superior in every way to flesh, bionic arms and legs stronger and faster, etc.
Some Iron Hands are supposedly gone so far as to really only have the brain and some geneseeds that can't be replaced left (which we have already replaced a lot of our acillians geneseeds with stuff like mechanical hearts and black blood etc.).
What would be the drawback of just making all our space marines in essence as cyborgified as possible from the start? If there's ever a need to switch back to flesh, cloning body parts and grafting is a thing too (Inquisitor Eisenhorn turned down an offer for a cybernetic hand after his was blown off, preferring a fresh one grafted).