Alejandro : I find this to be a very interesting topic. I would like to simply add that one of my teachers at the center where I study Japanese here in Chile seems to dislike using the word 'gaijin' as well, and prefers 'gaikokujin'. Her rationale was, if I remember correctly, that, while 'gaijin' is not derogatory in itself, 'gaikokujin' suggests a respect for the other person (being more formal), whereas the former has no such connotation, and could therefore be interpreted as being impolite.
Yuri : Alejandro, thank you for reading and answering.
Most Japanese people say the word “gaijin” without knowing that.
It might be causing troubles between people from foreign countries and Japanese. What can we do for that???