Just because you don't intend splitting the art into these categories to make people feel bad doesn't mean it wont. There are plenty of other websites that operate without separating users' works based on skill level(deviantart,furaffinity,etc.). If artworks really need to be split up into different groups there are many other ways to divide the boards. Honestly, this is only going to encourage an elitist type behavior that already exists within the artist community here, and lead to many works being put into advanced only to receive degrading comments because others don't find their work suitable for the advanced board.
And beyond that, just because someone's art looks better, doesn't mean they spent more time on it. People who are less skilled who spend a ton of time on their art will get less exposure because they wont be able to put it in the advanced board where most people will end up going to look for art. It's unfair to those who are trying their hardest to improve their work and spending tons of time on it who just don't have the same skills as more experienced artists.