Heh. While I agree that some kinks are clearly kinkier than others, I don't think they can be cleanly divided into tiers like this. Different people have radically different views of which things are equivalent.
If you can't write a letter that adequately clarifies your preferences, you'll get ODAO. If I want to write someone weird porn, I want to know exactly which weird porn they like best, not a vague general level of kinkiness they're okay with. 90% of fandom loves dubcon. 0.01% of fandom loves necrophilia. I would always write unrequested tattooing: they probably don't care enough to mention it one way or another. But I would never write unrequested infidelity: it's likely to be a massive deal-breaking squick that means they won't even read the fic.
It makes perfect sense for any given person to look at a list of kinks when trying to remember what to put on their DNW list. A ratings system is just going to lead to a lot of authors asking for clarification and/or being offended that their recipient thinks their favorite kink rates a black when they think it's a purple.
It's like that old kinkshaming wank!
If you can't write a letter that adequately clarifies your preferences, you'll get ODAO. If I want to write someone weird porn, I want to know exactly which weird porn they like best, not a vague general level of kinkiness they're okay with. 90% of fandom loves dubcon. 0.01% of fandom loves necrophilia. I would always write unrequested tattooing: they probably don't care enough to mention it one way or another. But I would never write unrequested infidelity: it's likely to be a massive deal-breaking squick that means they won't even read the fic.
It makes perfect sense for any given person to look at a list of kinks when trying to remember what to put on their DNW list. A ratings system is just going to lead to a lot of authors asking for clarification and/or being offended that their recipient thinks their favorite kink rates a black when they think it's a purple.