I've heard a lot of people saying this. They said the beginning of the movie was great but started falling apart in the second and third acts. I really think they went in thinking "what if we made Pikachu Deadpool" and went from there. Now part of me wonders how this would have ended up if Danny Devito got the role.
Ugh why is everyone so in love with wanting Danny Devito to voice Pikachu. He is too damn creepy!