Conversion

[callforjudgement]

I think the generally accepted standard for unfun/bastard role changes are those which invalidate a path to victory that a player might previously have relied on.

For example, if you need to kill all scum to win (e.g. Vanilla Townie), suddenly becoming a Cultist and needing to kill all Townies instead is pretty much a direct reversal of your path to victory, so all your efforts through the game so far now count backwards.

It's also bad to convert players to a role that's bad in its own right, but that's the fault of the resulting role, not of the role change itself.