My problem with most common cyborg characters is threefold.
One, don’t leave raw machinery out in the wind.
Two, don’t disregard the importance of, and the viability of, modifying the body’s systems instead of just bolting shit onto flesh.
Three, stop treating them like they’re either conflicted about their humanity or wickedly evil/perverse/have an amputation fetish.
Harden their bones with carbon nanostructures.
Reinforce their tendons and skin with cell-wall and tissue proteins synthesized based off of Golden Orb Weaver silk.
Increase their blood oxygen saturation and reduce their resting heart rate, increase the amount of and efficiency of mitochondria in skeletal muscles.
Use TCS to improve learning ability, use other forms of neuropathy to improve dynamic visual acuity.
Use scleral implants/surgery to widen the focus distance of their eyes, and wavefront ablation surgery to improve eyesight and lens clarity.
Add silicone pads with rare-earth magnets embedded in them to provide electrosensory abilities.
Use cochlear implants to protect their hearing from loud noises, but also improve their hearing sensitivity, both through minor amplification as well as through a steroid biogel applied to the cochlea.
Flush/clear the vestibular system and use nerve-growth-promoting biogel to increase sensitivity of vestibular sense of balance.
Add a subvocalization system to the layrnx; a small peizo element with some sort of transmission system.
This is just shit I’m thinking up off the top of my head. If you write a cybernetic character, don’t neglect the fleshy parts. Recognize the ability to improve and modify them.
Remember they aren’t just human meatbags with metal bolted on; they’re a unified system of parts, mechanical and organic, and those parts need to be able to keep up with eachother.