So, the first teasers are starting to go up for the new expansion.
The only new information is in the "Nightmare Tide" section and then only the last 5 paragraphs.
New rifts - Nightmare rifts, apparently unending. Don't really get the draw there.
Minions - something like the duty officers in Star Trek.
5 new levels - calling based rather than soul based.
New equipment slots - - you can unlock them for free per character by some sort of nebulous in game actions or unlock for the account by buying the digital upgrade. Those by account things outside of the soul packs have been extremely expensive, so enjoy the grind.
The real gem is in this clusterfuck of a bad idea: "The current plan is to ensure that the best gear in the game today lasts you all the way to level 65 – and a bit beyond." - Hey, if you're bored doing the same raids you've been doing for the past two years, don't worry, you'll still need to do them with 5 more levels and another year later!
The minion thing might be interesting. People liked the Star Trek version and WoW likes it enough to steal it with their own new expansion.