AbuseFilter provides a textarea for selecting the tags you want, which is seriously primitive. It isn't so bad now that erroneous tags can be deleted, but we could still do with something a lot nicer:
- Users could select the tag(s) they want from a jQuery.chosen type list (or the OOUI equivalent). This list would contain existing tags used by AbuseFilter.
- A new tag could be created using a custom input field. When an "Add" button is clicked, the tag gets added as an option to the tag selection list.
- Tag names would be validated properly (T92956). The current system allows users to create broken tags, like invalid,tag.
- Instead of exposing raw tag names, the "decoded stripped tag description" added in https://gerrit.wikimedia.org/r/211497 would be used to provide friendlier names.