There's a pretty believable-looking image going around on Reddit, brought to my attention by Blizzard Watch, which gives us a couple bits of interesting information.
The image is a set of enticements to pre-order Legion. In the fine print, it mentions that the game is expected to release "On or Before September 21st 2016," which implies that the game will be releasing some time in the summer.
Granted, I really hope that means early in the summer, because we don't want a full year of 6.2 (which would mean it would have to release in June, I think.)
The biggest part of this potential news - and I'd rate this far more "Leak" than "Rumor" - is that Demon Hunters will be playable for those who pre-order the expansion. It's likely that this means that DHs will be playable in the 7.0 patch.
At Gamescom, Blizzard talked about a pretty big opening event that would actually take us to the Broken Shore before the launch of the expansion itself (probably a pretty devastating battle where we'll lose some important people.)
Given that Demon Hunters will finish their starting experience at level 100 (starting at 98, most likely,) it's not really as if players decide to make their DHs their mains will have a ton of catching up to do - it'll be less than DKs had in Wrath, when they had to play through Outland while everyone else was heading to Northrend, or Monks who had to start from the bottom at level 1.
But I imagine this will be an interesting opportunity for raiding guilds to figure out how to integrate Demon Hunters into their groups and give some people time to try the DH out before they commit to leveling them up from 100-110.
This also makes me wonder if this means we'll be getting our Artifact Weapons early, but it remains to be seen.
Lots of news coming tomorrow, but this could be a little spoiler for that.