I actually didn't like JBH when I first heard it, but I guess it grew on me lol. I saw a comment on the subreddit for 5sos, saying that as their vocals get more advanced, the more parts Luke gets. Probably cause he has the most experience with the lead vocals, but imo all of them need more "solo songs" in general. Especially Calum, but I might be biased in saying that (huge Calum girl) xd