In the wiki live chat feature, I think it'd be good to have a feature for those with the proper rank be able to delete messages. With any online community, there will 100% be trolls, so there should be a way to get rid of messages that violate the community's rules.
Staff do not regularly read these forum boards. If you want your feedback to get to staff, the people who have the capacity to implement these changes, you should submit it to them directly using this form.
That being said, I would not hold out hope for a few reasons. Wikia seems happy abandoning chat since so many communities have already started using Discord instead. Also, chat isn't logged permanently (at least not publically) so trolling will disappear naturally over time.
FANDOM chat is effectively deprecated, but still running. Various comments from FANDOM staff suggest they won't be adding features to chat as it exists now. In theory if a bad bug appears they will fix it, but that isn't guaranteed either.