The bulk update request #10071 has been approved by @nonamethanks.
There's no point to having them as distinct tags. The other DLCs in the series (Artorias of the Abyss for DS1 and the Crowns for DS2) don't have tags. Any spoiler-related purposes have been obsolete for years. Ashes of Ariandel is especially bad as it doesn't even imply Dark Souls III and there isn't a tag for The Ringed City.