We all probably think "Insane" is hard enough for a level, but I'm just thinking: sometimes a level could be more than insane, and maybe the designer never intends to make a level like that, but I bet there are players who may find certain levels to be harder than "insanity." If a level is generally way too hard for a player to rate, they why not give them the freedom to let the designer know that BY rating it? I mean, there are already a lot of levels that have been rated as "insane," but are they really?
So pretty much, if a level is hard enough, it could warrant something more than "insane." But this is just my opinion, that's all. I'm not trying to say that we should make some levels that require mastery, but others may find a level fitting for it and they have their opinions.
Do you think it's reasonable to add another difficulty choice to rate levels by, like something above "insane?"