If this were to be a thing it should only be for Mentors and only able to swap to missing roles when a player leaves. I remember back in the day when I was doing my 2000 roulettes and the amount of times I could have swapped to a Tank or Healer [and sometimes did by leaving and rejoining losing my Mentor Roulette] was sickening. Pretty sure I lost around 70-100 roulettes because of this. In the end I just ended up having to Tank the last 1000.

That being said, I would only be up for this if it were only Mentors that could do it, and only if the mentor didn't start a vote kick. [Personally I don't think Mentors should be able to kick during their roulettes.] The last thing we want is people kicking new players to replace them.