@
RotRat and @
Icaruz hit the nail right on the head.
Detective Pikachu works because it looks like Pikachu. They weren't overzealous with the realism. All they did was give Pikachu eye color, some fluffy fur, and a detective hat. And it looks real enough to work as an illusion while also retaining the charm and spirit that the source material has. And for pretty much every other Pokemon in the movie, the same care and detail that Pikachu has is also applied. Sure, some Pokemon come off as scarier due to this added realism (Mewtwo, Greninja, Aipom), but I don't think it'll be much of a problem for viewers because these Pokemon will not be the main focus of the movie. Because of this, it's inviting enough for all kinds of people to enjoy.
Sonic, however, looks a lot more like a person that has been CGId than the actual character. The main detail that most people notice right off the bat is the eyes: Movie Sonic has two while Game Sonic has a more unique eye shape. Of course, not all Sonic characters are like this (Tails, Cream), but Sonic's large eye(s) are a pretty big defining feature. It's not
bad per se, but it's different. For most people, TOO different. Movie Sonic also doesn't retain the gloves or longer legs, instead looking like a very small runner. This is probably to emphasize that "gotta go fast" theme, but instead makes Movie Sonic seem off. And because it's the Sonic the Hedgehog movie, viewers are gonna have to deal with this for the full length of the film. This might put people off. Fans of the source material and the curious will see this movie, and I think it'll do well enough in the box office, but you can't ignore the possibly large amount of people being too unsettled by these changes to bother even watching the film.
Also, I'd like to talk about the music used in both trailers. Detective Pikachu used
Happy Together, a song about two people going through thick and thin and still being friends. This song captures the relationship between a Trainer and their Pokemon. Of course, the main character isn't a Trainer, but this relationship can still apply.
Whereas the Sonic movie uses
Gangsta's Paradise. How does this song relate to Sonic in any way, shape, or form? They could have at least used one of the Crush 40 songs from the Sonic games. That way people could at least link the Movie Sonic with the source material a little better. But no, instead we get a slower paced song about danger and gangs. The danger part I guess fits, because Sonic's facing off against Eggman and the military? But even then, that's a stretch.
TLDR: While Detective Pikachu stays loyal to the source material, the changes made to Sonic in the movie can easily make the film more off-putting to most viewers. The overall music choice of the trailers also influences what viewers will expect from the movie, and the Sonic movie trailer has chosen an unfitting song.
