It's also just a very cluttered film. Why do you need 4 priests and one nun and then all the arguing about what's going on in the house. Just really unneccessary.
I just rewatched the remake also (both are streaming now on Amazon) and was going to put up something soon!! I agree with you that it's not anything to write home about. The main improvement is that it actually tells a coherent story, although the story is pretty cliched. That, and Ryan Reynolds walking around shirtless displaying his perfect abs :(
RE: 'The Amityville Horror' (1979) Revisited: Actually, It's Not a Very Good Movie