The problem with horror films these days especially Counjuring franchise ones is "less plot and more effects, most importantly sound".
The realistic horror feel is being lost with too much visual effects and CG work.
With very intriguing storyline and with very less run time, alot has been told but not picturised. Valak the main charecter on whom the film is based on, wasn't given proper justification about its origin or it's end (can't give spoilers).
Unnecessary comic relief spoiled the scary feel and the child ghost is less paranormal and more alien. The Franchise must focus on making film much more interesting and scary than showing unnecessary and artificial CG work.