I understand your point. However, the problem of WHAT are we expressing and externalizing remains. Otherwise, would a stock anaylst creating a formula that is meant to explain some cyclical movements in the stock market be an artist as well?
What is the nature of the creativity taking place in art? My explanation of what creativity in art might be is ultimately that there is no REAL creativity in art. From nothing derives nothing. The artist simply elaborates his internal world or the external world filtered through his internal world. The matter is already given. Art is process much more than content. This explains why Van Gogh's landscapes are so different than those of any other artist, for example. "Process" refers less to one's technical ability than to one own's history, personality and attitude as the determining factors.
It may be that THERE IS NO CREATION IN ART, ONLY GENERATION, in the philosophical acceptation: God creates (=from nothing)/man generates (=from something already existing, like his/her semen/ovule).