A lot can depend on the art and the instructors involved. What are you interested in?
I would not say that Japanese arts are hard to learn. I think most people new to Japan might not be ready for the amount of specialized vocabulary and the language issues involved in studying under someone who probably knows very little English. However, there is nothing esoteric or mysterious about Japanese arts that prohibit non-Japanese from being successful. I know several non-Japanese who have become masters in their art and are recognized and respected by Japanese in the same field.
PS: welcome to JREF