may I ask, just sitting there afk? not even need to tag the mob?
A trick I can think of to make the invasion faster could be let a low lvl tank the boss and let the high lvl healer heals the tank. Yesterday there was only llike 5 ally and 1 horde fighting the entire invasion in tanaris, guess nobody wants to do it now since the reward is meh..what can I do with the shards?

Any usage of the shards besides item from those NPC? to me those are not very useful.
Since after the afk exp nerve, they also buff the demon. Solo demon grant quite good exp but it can be screwed by any lvl100 that tag it in the mid of fight.

afk doesn't give much exp after the nerf, tagging mob gives more, bliz buff the mob exp..those boss mob gives more exp.