Originally Posted by
dacoolist
I'm speaking on just the past at least (It doesn't mean they won't do something different this time around obviously haha) - Most of the time, Blizzard drops the Pre-Patch (this ones called: 7.0 or 7.0.3, because who the hell calls it a name anymore [Windows 10, MacOS 10.12 .. etc etc]) roughly 1 to 2 months ahead of the next expansion. During this time Blizzard usually ramps up events such as the demon invasion from TBC portal, Zombies from Wrath, Taking back the troll islands (I don't know what you filthy ass alliance did back then) from CATA/Elemental invasion, The scenario from dropping a bomb on theramore for MOP, and the Blasted lands Iron Horde invasion for WOD to pretty much the launch of the game where blizzard flips a switch, and quests/zones become available.
- - - Updated - - -
If you're looking for a time table, that VERY LATEST blizzard could possible release the pre-patch (7.0.3) is August 2nd, which gives only 4 weeks for the launch event, getting everything situated in class's before Legion hits on August 30th.
I am GUESSING the patch will hit July 26th, that way we have at least 5 weeks to get used to our newly revamped class's, and all that. But this is me guessing