These changes aren't so bad, they are just trying to define roles. If you don't want to heal then advertise yourself as a blackmage and say you'll only nuke or start a party with two conjurers and have one heal and you nuke.

Maybe THM should be main tank healer because mostly everyone else should not be getting hit if they position themselves right. So maybe conjurer is supposed to be the nuker and if for some reason your group messes up a little you throw in a curaga here and there? I haven't played yet so I don't know but that seems very plausible!