(Recent) bands that didn't get good until they figured out what they actually were:
- Good Charlotte were average punk until they starting making outstanding new-New-Wave pop
- Fallout Boy are average emo but great power-pop
- Panic at the Disco's new sound is more Queen than the single-note emo of their earlier efforts. Thankfully.
Notably, all started out in the pop-punk/emo tradition before branching out. Can you think of any others?