I understand about redundancy but isn't a wire or even several wires more vulnerable than a control rod? I mean its comparatively easy to damage/disrupt a wire/s compared to a control rod, isn't it?
I would say that a control rod is, although very well understood and perfectly safe, more vulnerable than a cable. Think about it this way. What is that cable doing. Effectively nothing. It sits there with those magical little electrical signals passing through it. What does a control rod do. It is constantly moving, it is never still, there are always small loads being applied to it. Now I am not saying that control rods are unsafe, but there are plenty of examples of mechanical control failures, whether they be due to poor maintenance, metal fatigue, design failure etc. Of course there are also examples of cable failure due to similar reasons. Overall though there is potentially less strain and less chance of failure to a cable.
Probably each engine will have its own alternator but will there be additional back up systems such at the ram air turbine that airliners carry?
Bear in mind that the RAT is primarily there for hydraulics, not electrical power (on my type anyway). There is so much electrical redundancy that the RAT comes at the end of a VERY long line of electrical back ups.
As has been touched on by another poster if you had any concerns about the flight control system on any aircraft then it should be with the hydraulic side rather than the electrical generation or transmission side.