Fan art is fun, and it is a good community building thing for a fanbase. However, (this is my personal opinion based on my beliefs so please don't attack me and take what I say as an attack against you) when you build a character for the sole reason of gender bending or colorfulness (Sex appeal and half nakedness to full nakedness, is what I mean) that seems a bit iffy to me. Bowsetta sounds like she could be a good character if these things were dropped. Think about it, she could be a sort of evil peach! Like a wa-peach. Maybe she could be bowser's wife or related to him in some way? She doesn't have to be sexy or bowser changing genders. I think it is more fun and clean that way and it doesn't get into the whole semi-pornographic way.
That is a good example of GOOD FUN NONCOLORFUL (you know what I mean) fanart. Nothing is explicit, it is taking a character (boo) and making it into a princess. It is a fun, cute visualization that adds to the mario fan universe. It makes me wonder what it would be like to have her in a game and what her personality is.
I honestly think more princesses in the mario universe would be cool. I mean, we only really have peach, daisy, rosalina, and pauline. They are all under utilized as is (except for peach, and rosalina to an extent) and Mario does travel to different worlds and kingdoms all the time. Why not go all super mario land and have him save someone else than peach?