I did a search for other discussion of cybernetics and found very little. Since it's something I write about, I thought I'd throw out some ideas and see if they stick.
First, the aim of cybernetic enhancements is to add more tactical options and advantages to soldiers - things that can't be delivered by other means. You wouldn't pull out a soldier's eyes to add infrared vision if that soldier can just put on IR goggles, nor would you replace his arms when he can be sent off to the gym to exercise more.
Second, PHALANX's goal with cybernetic augmentation is to take a different tack in the war. Stealing enemy technology for weapons, armor, psionics, etc is trying to beat the enemy at their own game; as the enemy neglects useful cybernetic augmentation of their own troops, turning to augmentation of PHALANX soldiers is attempting to change the rules.
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With that in mind, the first implant I'd like to propose is a Suspension system. A suspension system uses perfluorcarbon solutions to provide emergency oxygen to the bloodstream in order to stave off brain death until medical intervention can (hopefully) repair whatever damage caused the system to turn on. Development of it arises naturally from the ideas presented in the Alien Breathing Apparatus.
Soldiers with a suspension system implanted are less likely to die when disabled by damage to the limbs or torso. These soldiers will still require lengthy recovery times but their odds of making it to a hospital in the first place are much greater than unaugmented soldiers. Unfortunately, a suspension system is relatively invasive, and is not compatible with any other implants.
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The second implant is coupled with a line of external devices. I expect them to be named something better later but for now I'm referring to them as holo-grenades. These devices visually resemble caltrops; technically they can function like them, but the shape was settled on only to make sure that at least one prong was facing upwards when the device is thrown.
Once the grenade lands, it projects an image of a PHALANX soldier onto a nearby surface (or smoke cloud), drawing fire away from real soldiers, possibly even triggering reaction fire. On its own, the grenade lacks the processing power to have its 'soldier' behave realistically, and the nature of the aliens means that the more enemies seeing it, the less likely that any of them will bite. Sheevar can only be fooled by upgraded models (requiring laser tech to provide enough heat for an IR signature).
A soldier augmented with a Distraction suite (requirement: Hovernet autopsy), however, can learn to manipulate the image produced by the grenade. With a cyborg soldier controlling the image, it reacts realistically to its environment, including enemy fire, and is significantly more likely to actually work. At higher skill and technology levels, PHALANX can even produce mobile drones, shoulder-mounted projectors, and the like, all to draw fire away from precious soldiers.
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Obviously rough draft material. I might be able to come up with more, but how are these sounding?