The 6.1 PTR isn't even live yet, but datamining continues apace, and the folks at Wowhead have certainly dug up a doozy for us. Apparently as part of the legendary questline, we'll be getting the first ever legendary follower, namely Garona Halforcen, the infamous Shadow Council assassin. If you're curious about what a legendary follower gets, it's impressive.
It's very interesting to see the quest open up in this way, really . It broadens the idea of the kinds of rewards you can get from a legendary chain, and it also makes me hope that we might see other such followers. Perhaps my hope that Maraad can make a comeback isn't entirely unwarranted.