Once you know it's a demon from Hell...

...then it's really not all that scary. After all, demons love to taunt the innocent and terrify them as well.

It's like Lorraine Warren being taunted by Valak ever since the Amityville seance and taking on the form of a nun to mock her faith, you know what to expect from then on. What I found original about Conjuring 2 was how Valak used the ghost of Bill Wilkins as a puppet for its own ends, and even thought of taunting the children with the Crooked Man zoetrope for good measure.

I was nervous of A:C at first, but once the demon reveal is over, then you actually relax a bit, as you know what to expect. However, it will make the forthcoming Nun movie rather limited, if it IS Valak once again. I mean, it would have to be set at a convent, right?