While the current chat profanity filter is swell at its job, players would benefit from the ability to customise it further. Allowing players to add, remove and replace entries clientside in the profanity replacement list could add a lot of customisation to the experience players get from messages in public chat.
For example, players could replace some profane words with silly or innocent words, akin to GMT, such as replacing the word "f**k" with "hug", removing the profane words but still making the sentences sensible without the asterisks interrupting the flow of the sentences. Additionally, players could add entries for words they don't want to see that perhaps weren't filtered by default. Allowing players to remove entries from the list would let them be specific with which words they are okay with seeing, and which words they are not.
Of course, there needs to be an option to restore the default filter list, in the event it's needed.