The biggest challenge IMO is Haptic (sense of touch and resistance) feedback.
It is nearly impossible to emulate the sense of touch and force that surgeon's arms feel during surgery using robotic arms.
One of the important sensory input to a surgeon is sense of force or resistance. Different tissues and vessels have different structural profile. You have to apply right amount of force to get the precise cut thru different types of tissues or suture with the right level of tightening.
I think what is gained with precise movements and enhanced 3D vision is somewhat negated by lack of precise haptic feedback.
very true in addition, looking at a monitor no matter how hi-def you lose perspective and get into the tunnel vision syndrome, where you lose situational awareness, so you fixed the ripped peritoneal membrane but you could not see until to late, that the person was bleeding out from another peripheral location.