Why would blizz shut this down?
Until blizzard themselves make legacy servers they will not gain anything from shutting Nost/Elys down. And until they do they wont be hunting private servers and especially not this.
Yes they are aware of this project, they are well aware. The previous shutdown of Nost made it quite clear to them there is a big demand for legacy.
But you have to listen to what they say and they have never said anything about that they are against private servers. As long as the private server projects arent making money out of the game.
They have said they Love legacy but they dont know how they could make it happen at this point. The undertaking for them to implement this is too big to just "push a button".
And until they have made it clear of how they will handle it, Ion Hazzikostas himself said "we will have to let the nostalgia" handle it.
This project enables every party to get what they want. Blizz can calm and in their own pace decide how to handle their legacy. Meanwhile the screaming masses of the private server community get their server thus putting the lid on the rage.
Trust me, Blizzard dont want to anger their fans and should they shut this down it would be like putting out a fire with gasoline.