That’s called “Ecchi” and we already have a tag for that.
I feel like that’s the main problem. What counts as fanservice for me might not be fanservice for you, and vice versa. I’m getting annoyed by weird camera angles and certain “lucky” events in otherwise clean manga, but other stuff doesn’t even register for me, like e.g. here Naphthalene finding (light) fan service in something that I thought was free of it. Although I guess people can just downvote the tag if they disagree.
edit: Thinking more about it, “level of fanservice” sounds more like a scale people vote on than a series of tags… but I guess tags would be better than nothing.
