I don't like getting CT raids but when I sign up for a roulette I acknowledge that it's random and if I'm not willing to do whatever content the roulette throws at me, I don't queue up. I would only be okay with blocking out duties if there was a hard limit of like 1-2 things you can block out from getting. But I really don't feel it's a necessary feature as the point of roulettes is to keep the older content active and help new players get through it.