It should be, especially the legendary ones like how Beethoven's Symphony No. 10 was further extrapolated and finished. As the AI keeps growing and seep deep into lives of humans. The seeds that are sowed has to be cultivated hence endorsing such practices can contribute creating more of such arts to the esteemed cultural world. But I make it clear that still the AI creation has to be an identity of itself and should be treated and given to the public as a blended artform rather that displaying the creator alone. By this way the criticism ,if any is pointed against can be both treated as not just the artist himself but also the ai counterpart.

The artist who spend years in such a painting has to be credited where the hardwork he invested. Merely rejecting the involvement of AI is in fact a way of not accepeting and respecting his hardwork given we have a provision to make it complete. You can still use such poetic arguments like brushstokes being his voice. An incomplete painting will be his voice in mute and completion of it is always better than having nothing.

Bethoven made it unfinished, not because of his lack of interest to finish it but for his health deterioration in his last years. He mainly focus of other simple compostions rather than such complex ones. In short, he didnt make it unfinished for a reason, if for, the reason being his health which was against his will and not the reason he made. AI pretending to know his infact a devoloping topic, it can be incorporated with behavioral charactersics. I would recommend completing such masterpieces rather than leaving them impact and not respecting the hardwork that they invested and couldnt make it full way. The debate is not about how you are fasioned.