I would be more ok with Town Traitor if like the traitor became Mafioso once Mafia is dead or something like that.
I try to keep them reasonable but I don't stick to a defined list. I think my All Anys usually end up with more neutrals than an average game but the other proportions tend to be similar. Having the mystery of whether or not Town has majority is part of the fun and makes it less likely for evils to be like "hey there's 5 Town and 6 evil roles, let's just not vote and kill them off tonight".