For me, the first one that comes to mind is The Navel (Hard), because Duty Roulette: Trials likes to give me Titan HM roughly 75% of the time.

Please make Granite Gaols immune to damage until the immediately-following Landslide has been cast. (HM only, EX is fine)

Sometimes I'm the unlucky winner of Landslide Roulette when I'm trapped in a jail, but much more often I see some other poor player go flying off because the party breaks their Gaol while a Landslide is aimed directly at them.

I don't think this is fair, or a good design (for blind matchmaking): it is 100% not the victim's fault in any way, yet it completely removes the player from the fight (no Raise, even). You are basically punishing a player because everyone else doesn't understand mechanics when they queue DF Roulette (or doesn't care).