Blizz steals a lot of things. Just from GW2, they stole:
Group bosses / tagless kills (starting with Timeless Isle)
(Sad attempts at) level-less zones
And what did GW2 get out of it?
WoW definitely got the better end of the deal.
Many alts! Handle it!
"A condescending answer might as well not be an answer at all."