I want RDM to be designed like this:

You have 3 abilities that swap your role between Tank, Healer or DPS. You need to pick your role before entering a dungeon and you can not swap roles in a dungeon or during battle. Some sign to inform people what role you are in would be helpful.

All the other abilities you have are always the same regardless of what role you are in, meaning you have a selection of tanking, healing and damage dealing abilities, but depending on which role you are in, all abilities act slightly differently, boosting the stats needed for that role, like making healing abilities more effective in the Healer role, or even adding extra effects while in the proper role, for example a small Regen effect.