Here is the deal. Johnny Blaze was possessed by an evil and dangerous entity called Zarathos who was a fundamentally evil being. What good he did was due to the constant inner struggle with Johnny Blaze, who was a very good man.
Dan Ketch was a kid from Brooklyn what was possessed by the Spirit of Vengeance, who was fundamentally a good spirit. And though they both struggled for control, the entity and its host trusted one another and worked together.
What this movie does is tries to mesh Blaze and Ketch and the spirits that possess them together...and it doesn't work.
The amalgamation robs the story of the intense inner turmoil and the fight between Blaze and the evil entity possessing him...that was a very good, very fun, very intense story that this film NEVER tells.
And Dan Ketch, the story wasn't as interesting, but it was still good focused more on the community, the town, the family life and the stress that the entity caused in the hosts personal life...it was still a very good story, it was still very fun, and it was, again, NEVER told here.
By trying to push the two of them together--including the supporting cast--the movie loses the stories from BOTH of them. What you get instead is. vapidity, and all the CGI in the world can't save a movie with no story.
There was no direction. There was no grand scheme. There were no real characters. It tried to be two different things at the exact same time and, because of that, didn't tell a story.
It ended up being special effects without a story and nothing more.
Had it chosen a direction, either direction, even an entirely new direction, the movie could have told a story. Unfortunately for everyone involved it didn't.