The raid is Ny'alotha and every boss is one of three things: minion of an Old God, corrupted by an Old God, or N'zoth (an Old God)
The leak explicitly says "8.3 won't be about old gods or the shadowlands. It will be all about what will be know as the great 'battle for azeroth', a big conflict between both factions resulting in a completely ruined Azeroth. Both Orgrimmar and Stormwind will be heavily bombarded, few quite important characters will die and so on."
Every word of this is contradicted by the 8.3 PTR