Yes, you're quite right about the dedication. Really, I was thinking mostly that choosing other 'roles' would just have been fun, and I wasn't really all that concerned with whether or not people stick to them really really closely or anything. I never really expected anyone to be able to do it. But perhaps the fact that it would simply be for humour/entertainment reasons means it's not a very good idea, either.
I should perhaps take these things more seriously? Probably.
I guess making sure people took the game seriously but keeping it all in good fun is constantly a precarious balance. I don't expect extreme dedication out of anyone, but perhaps I should expect more? I don't quite know.
Obviously it can't hurt at all to tell people that they should try to play differently than they have in the past in a (the next?) game, but I don't think we should put so much pressure on such that it be 'bad' if someone slips back into their old habits, which they will most likely do, anyway. Still, if perhaps there is some rhyme or reason to the new style of play, it might actually be easier for someone to try and play differently? Thus, maybe choosing certain roles/styles (not necessarily other 'Downers as in my one idea), would actually help? *shrugs*