Got an idea for new content:
Do something unique your class have:
ROGUE: poison making = create your own poisons, set the doses, mix them together and discover new effects.
HUNTER: pet caring = modify the appearance of your pet. Change its colours or skeleton. Teach him new animations. Eventually make him wear armor! (aesthetics only)
MAGE: spellcrafting = customize the particles of some of your spells. That won't be easy! (limited graphical changes).
PRIEST: inquisition = follow unique daily quests to discover heretics around Azeroth. Track them, find and punish them (no objective tracking).
DEATH KNIGHT: necromancy = learn being a caster (switchable "spec", abilities from melee to range). (i'm sacrificing here my own necromancer class idea)
DRUID: dreaming = create your own little Emerald Dream. (like your little instanced home, grow plants and edit terrain)
SHAMAN: worldmending = follow unique daily quests to discover disturbed powerful elementals around Azeroth. Track them, find and threat them (no objective tracking).
WARLOCK: demonic lab = create/discover/summon new demons or modify their body. Also choose the weapons for some of your demons.
PALADIN: justice = avenge evil acts through daily quests! Investigate and find the true criminal, do not kill the wrong guy! (no objective tracking).
MONK: training master = train your own student! Choose your pupil and train him/her till being an awesome spiritual monk. Make him fight vs other players' students. (AI only, you spectate)
WARRIOR: superheroism = save innocent people around Azeroth from evil persons. Timed quests! (aesthetic rewards)
DEMON HUNTER: felhunting = follow unique daily quests to discover demons around Azeroth. Track them, find and punish them (no objective tracking).
NOTE: this thing is not meant to be mandatory. Rewards are aesthetic only.
Get back some RPG! And chill out the rushing for balance only