Thank you a lot for your answers. But I am wondering what you mean by "aptitude" ?
What kind of aptitude is completly necessary to be ATCO ? Multitasking ? Speaking performances ? Virtual 3D vision ? taking decisions ?
Can you explain what is so difficult to learn ? For example, you meant it is more difficult to be ATCO than airliners pilot. Why ? I though flying in 3D and multitasking in flight was pretty complicated (I just have a PPL).
For example, can you explain what is the typical difficulties for you to make you job ?