How to improve engine-out handling on a multi-engined aircraft?
Yes providing a longer vertical tail arm is very beneficial for control in case of engine failure.

During the pre-design phase of an aeroplane the Tail Volumes are determined: area of horizontal and vertical tail, times the moment arm. This answer gives more info on some statistical data and methods.

Of course, optimal dimensioning is paramount since we're dealing with aerodynamics and we want to limit drag. The tail arm is usually limited to the useful fuselage length, leaving the tail area to be the main design parameter.