The content cycle for World of Warcraft has a predictable up-and-down to it. Right now we're in the pre-expansion lull, where all of the big things are done in the current content expansion and we're waiting for the pre-patch event to lead into the next such expansion. Thanks to the streaming community, we get to see what's in the Beta well before the fact (either by watching their streams or the videos posted to YouTube), so the sensible among us are using this time to get ready.
For me, this means cleaning out the clutter in the banks of my characters. It means finishing up the last rounds of Legendary Quest work on the last alternate characters, leveling sub-capped characters up so they're in a position to move immediately into the new content, and working that Auction House as best you can to help build up the warchest once more in anticipation of the needs of the new content.
For a lot of people, especially high-end raiders and PVP players, this also means reducing their playtime on Live in favor of Beta (if they have access) or some other option. The release of Overwatch hit just at the right time, therefore, to keep these players on the Blizzard reservation and not messing with non-Blizzard games. (A lot of World of Warcraft players do Hearthstone, Diablo 3, Heroes of the Storm, or Starcraft 2 on the side to play when they want a break from Azeroth.) Some stay in the world, but swap media and get into the comics, novels, and now the movie. Blizzard is very keen to keep its audience on the reservation, getting revenue one way or another, at all times.
It's a good time to take a break, and many do. Me? I've got paid game time through January, so I'm making use of it to get ready for Legion.