The main shtick of the Borg is lack of individuality, homogeneity; one borg being functionally no different from the rest. They are assimilated with nanobots and from those nanobots implants are grown. Implants that are inserted surgically could be manufactured to all be the same.
The Borg drones here all supposedly serve the same purpose, yet each has a different set of implants on their heads alone.
Is there a reason for their lack of homogeneity? Is this some small advantage they try to hold by not having too much redundancy? (E.g. implant A has a weakness against a species' tech but implants B, C, and D on the other drones don't).
Despite this there would be advantages to having identical implants in that repair and recycling of implants would be smoother and more efficient (something I know the Borg really dig).
Why don't all Borg have exactly the same implants?