Some issues would even be fixable by letting players self-identify for the DF and check boxes for "Hardcore," "Standard," or "Casual."

If you're a hardcore player and want to play with like-minded individuals who skip all CS and try to speedrun, you only check HC. New/Relaxed people who watch every CS and are still learning the dungeon choose Casual. If you don't care who you group with, you can check all three.

Of course there will be noobs that think they're hardcore, and the "Standard" option would still be a gamble, but any kind of differentiation of skill/playstyle is a step above the big melting pot we have now.