Too little, too late, it cannot be salvaged.
People who liked D3 from the start will still like the game. The majority, including the entire fanbase from the previous Diablo games, either hates D3 or gave it a "meh" and walked away from it a very long time ago.
Hey Blizzard, guess how effective your attempts to "give the series a broader appeal" were? And by the way, I think this is happening every time one of the industry meatheads is tasked with trying to broaden a franchise's appeal: It had ZERO effectiveness in increasing the player base, and if anything decreased it.
My three younger brothers are right in the key demographic that should have been the target for D3. Also, they had not played the previous Diablo games. Guess how much interested they had in D3? NONE.
So THERE is what your efforts to broaden the appeal, while ruining the series, amounted to.
NOTHING!