[Tsundere]

I don't think we're so desperate for reasonable RP that people should have to tag their characters as "reacts appropriately to genuine threats". I'm going to say outright that I don't like this idea, and while you stated that it isn't meant to be an elitist circle-jerk...well, that's how it comes off.

MOST people typically don't exaggerate their character's abilities beyond what they can do via in game mechanics, and whether or not the abilities are perfectly justified for the character to have, you really don't see many people legitimately roleplaying throwing another character through a wall. The edgelord minority will remain the edgelord minority.

Level 60 characters have been described as superhuman and incredibly capable as opposed to the average human/citizen (the consensus among many being that an untrained human with a normal career and no outstanding qualities has about the ability of an un-LE'd level 20-30 character). While this doesn't entirely excuse some levels of power that people RP as, I really think that the combatants we see are capable of sparring eachother without breaking their bones in the process.

Roleplaying a completely invulnerable character is bad RP. I can't bring myself to sugarcoat it by saying I don't want to mess with other peoples' fun, but I'm not doing that, just insulting their idea of it. A player must use their judgement when deciding whether or not a situation poses legitimate threat to their character--it's just not appropriate to end up killed in a spar when the other character had no intent of doing such. Get wrecked in a dungeon in character? Yes, that's a dangerous situation, and you should regard it as such. Get attacked ICly by someone with malicious intent? Dangerous situation. Omitting any possible injury or true danger from situations that could harm your character is poor writing.

I really just don't feel that there's a point to hardcore mode. Anyone with the cognitive ability to differentiate between a spar and a threatening situation should be expected to respond accordingly. You might as well just state 'I'm not too attached to my character to let them die if they logically should' and leave it at that.