Reconsidering this question, I am dubious as to the validity of the assumption that futuristic cyborgs actually are bad shots. In Terminator 2, Arnold has a few opportunities to shoot at the T-1000 (with a sawed-off shotgun, 9mm handgun and M4 that I can recall). Every single shot he fires at the T-1000 hits center mass, with the exception of a shotgun headshot when the T-1000 pries open the elevator doors in the asylum. Apart from that, we see Arnold sweeping an area swarming with policeman with minigun fire and hitting exactly zero people (which was his goal), and shooting an awful lot of kneecaps (again, intentional). I'd say his hit ratio for intended targets is in the range of 99% or so. That's pretty damn good. The T-1000 has a similar hit ratio, they just happen to all go into Arnold rather than vulnerable humans. In fact, the only person in that movie who completely whiffs on shooting is Sarah when she goes after Dyson and fires out 30 rounds against an unsuspecting target only to land a single arm shot.
It's been long enough since I've seen any other futuristic cyborg shooting media that I don't remember their accuracy, but it seems to me the original Terminator had Arnold take out an entire police station with robotic accuracy. So, I'm changing my answer to "they don't miss a lot."