For what it’s worth, when the original Detective Pikachu game was first announced, fans actually started a petition drive to get Danny Devito cast in the role.
What makes it even more surprising is that the title character is going to be unlike the traditional view of Pikachu.
The word is that the voice role of the Pokemon could go to somebody like Hugh Jackman or The Rock, which is not the sort of name we were expecting.
Though, based on the description here of Pikachu being “gruff-talking,” it certainly fits.