Maybe implementing a "required minimum" for tags on submissions? Like you need at least 4 or 5 or else you can't make the submission public. It's not a 100% fix but it will get people to start tagging their submissions appropriately.
As for muting I would prefer to select what exactly I'd like to mute individually. Like journals, submissions, commission announcements,etc. Rather than muting the users activity as a whole. I would also like an option to select multiple users at once and select what activity I'd like to mute from that group.
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