In regards to my own project, when I say "servo motor" I am not referring to the integrated RC Hobby type of system. Rather, I am looking at the type of servo that uses a separate motor and controller. The controllers use feedback from an external potentiometer, or a quadrature encoder. These typically involved a number of parameters that must be set, and can sometimes have fairly complex in terms of what the Arduino is capable of handling. A PID control system, which you might recognize.
My own project (for which I am simply evaluating the feasibility), is to create a Tinkerbell character by suspending a 6" ball of LED's from two cords located in the upper corners of the stage opening. The cords are on a motorized reel, controlled by a DMX signal. I was initially hoping to have a fairly precise positioning system that can be pre-programmed. But, I might simplify it to be just a live joystick control that only controls the speed of the motors.
Can you describe some of your projects that involved motors?