Why do most commercial airplanes use hydraulics instead of electric/servo motors? I'm sure it's possible to use servo motors to get precise control of the ailerons, elevators or the rudder. But still, hydraulics are widely used instead. 

Hydraulics do have a disadvantage that a damage to the hydraulic pipes can cause loss of control. Even with redundancy, there are cases where all three hydraulic lines get damaged at the same time and there's complete loss of control (can't remember the example). I think in some smaller aircrafts servo motors are used. But why not in the larger ones. Is it because of the torque required? 

What are the issues with using electric motors?
If used what are the safety concerns?
In terms of safety, how different are they from hydraulics?
I'm sure it's possible to use servo motors to get precise control of the ailerons, elevators or the rudder.


No, it isn't. Primary flight control actuators require both rather high forces and quick response time. Electric motors can provide either, but both at the same time is a problem. Hydraulics is still better for that combination.

Note that other actuators that don't require the fast response time (like flaps, gear or horizontal stabilizer foreplane (elevator trim)) are electric in some aircraft.