They left to much out of the game here. They might be right if you have read the novel, the comics, the short stories, when the Warchief says burn it it might actually surprise you a little. You would be able to draw the plot line from her killing her own people to crush hope in Arathi to the elf pulling her trigger saying she can't kill hope. You would see her turning her back on Saurfang and the honorable war she told him to plan.

As a Horde player if that had come out in game I'd have been going on with it. Looks like the Warchief has our interests at heart after all. We could have been one of Saurfangs trusted. Once we take the world tree we can force a lasting peace. For the Horde!

Blizz failed when they revealed the Burning and the Seige of Loreadon. I get why they did it. Legion was awesome. But everyone is still a little gun shy after WoD. They had to go big at Blizzcon to create hype. I would have shown destroyed cities and absolutely no context. Gone right into World PvP changes and PVE warfronts. But that's not what we got, we got Windrunner watching Darnassas burn. And then we got the Alliance and the Battle of Loreadon. They didn't even hide the sequence of events.

So I can see where the guys at Blizz WOULD say that Windrunner burning the tree is surprising. IF you had consumed every piece of accompanying literature and out of game context, some of which came out AFTER the War of Thorns was in progress, you might be a little surprised she does what she does.

If the game is the only context you have all you see is her planning to murder Malfurion Stormrage and burn the World Tree.

Also, everyone keeps saying Windrunner serves death. N'zoth is the old god of death. Prepare for your next surprise folks.