I tested as an INTJ once after I found myself as an INFJ. When I read somewhere that 3s put their emotions on the back burner to "Achieve" their current goal, it made perfect sense to me why another test typed me as such. There is no doubt that I am a feeler.
Most 3s (based on statistics that I have seen) are associated with Extroversion and Thinking. Personally I have a very conflicted nature, and that's not because I am a teen. It's always been this way.
I am not too worried about my outward appearance anymore, I can safely say I have become a assertive healthy 3.
What you said about 3w4s being artists makes perfect sense for me, though I prefer to be a psychologist. More specifically a Spiritual Psychologist, for religious purposes. (Lutheran)