Making it mandatory and running with a DF tank who doesn't mitigate will let me know everything there is to know if he/she continues to ignore mitigations after I offer them advice. It'll help me sort out the ones who I can kick or the ones who I shouldn't carry and risk making an even bigger mess at the upper level dungeons because they are prone to ignoring advice. Really, having the Hall of Novices be a standard would help raise the skill level of players drastically. It shouldn't be the case where if I use a role action Rampart / Reprisal, that I'm suddenly better than 50% of the tanks who queue up in DF. It just.. boggles the mind.