The best way I can describe them would be as "WoW" zones. They would be zones where the mechanics of the game would shift in such a way that characters would regen health and mana rather rapidly, rather than require a rez shrine. Further, the once every 60 seconds or so mechanic that heals you of various debillitating damage would function once every four minutes or so.
Finally, each mob slain would provide XP.
These zones would be exclusively solo. You could not enter them with teams. You would find solo level bosses that would still provide decent, at least sellable loot.
The most important aspect of this is that you would regen. Even if they incorporated this into the current zones I'd be pretty happy...
but regen is extremely useful for solo play, especially for Caster types.
The regen would be percentage based, regening a portion of your HP and SP every tick... such as 10% or 15% or whatever. You would only regen when not in combat.