I am really taken aback by this - the watercolor/ink style may be a little bit unusual these days, but it's not as though animation has never been done in this style before, nor that artwork of this style is completely alien. There is a ton of this stuff.
Nor is this film extremely minimalist, and minimalism been done before too.
I'm starting to feel that the overly-detailed, extremely complicated CG animation and action scenes in most movies are having an adverse affect on our expectations, so we are becoming less able to appreciate something simple.
I could tie this back to software - so much of what we deal with evolves over time to be rather complicated, with a million features, and we beg for more.
Geez, things can be simple. It's not "unfinished" to be simple.