I'm thinking the best part is very well defined and balanced classes
Maybe class quests as well.Which if you were say a paladin, you would go through this chain, working for your holy order and getting things like:
Crusaders Insignia - Magical trinket, 5 all stats , 10 charges of holy light...
I'm not sure how it culd be done, or if it's in the game already, but maybe a health-regeneration aura, just 1% per second or so.
Trolls in the Warcraft universe are said to have regeneration powers.