I have a suggestion. Instead of an automatic approval system, keep the user/moderator reviews but limit how much sentences people can use to describe their dragons.
And add a few scroll wheels with pre made aspects, such as: Affinity(Neutral/Agressive/Passive), combat orientations(PVP, NPC),abilities/spells, and personality. Exept keep the abilities close to the breed. For example a Brute dragon is not going to have the same options as a Shallow Water dragon. You already have the sort of guide lines on the Dragon Cave wiki. But have variety for each breed so not everyone is the same.
Reducing how much a person can type will reduce cohesive vulgarity and with less to read the moderators should be able to sort through descriptions faster.
But keep a text box so people can still put their own back story to their dragons, so it still is personalized but limited.
(On a side note, I have noticed with games that reduce player input such as HearthStone that has taken away the ability to chat there is little extreme player harassment)
Anyways thank you for listening.