My summary: 1st priority is to prevent the fastest farming classes to class change to the lowest farming classes that have the highest pvp endgame potential = supports, inclusing sws. So its fine to have more than 1 group for now.
Second priority: oly fatming: For da and es, they can have that penalty that can only change from it, not change to it, inside second group. I would argue to include necro.
Third priority: pve disbalances within 2nd group: If you care enough, you end up with 3 groups as in the beginning of post. If not, 2 groups. Either way is fine for me.