I think it's appropriate for the song.... the amp itself sounds fine, it's just they're using that thick washy chorus from the 80's, which is how the original was.
So I finally watched this. 2 minutes in is where it goes to flaming fizzshitcakes.
Then they try to sing a duo falsetto whoo-whoo whoo-whoooo that killed my house plants.
Given that he was playing a signature song by and artist that is so different from anyone else, I thought Adam Levine did a passable job. What was missing was the passion that the song demands. They performed it, rather than felt it.