tbr, even though Bakugou developed and matured his crash, unapologetic outbursts are part of his personality, I don't think that could just be taken away from him despite how much he changed. He's a character that typically is calm when he's left with his thoughts or when strategising to beat his opponents but when he's in a social setting or facing off an enemy outright his brash personality takes priority.
Though I feel like bakugou being placed at 15th was just outright cruel, despite his antics he still gets the job done and also the public has seen with their own two eyes him saving all might and defeating AFO I don't understand how he wouldn't have been placed higher if the rankings are based on popularity like were lead to believe.
I really don't know why Horikoshi backed away from Bakuto's character development. At the start he was an emotionally conceited brat who was always angry, but along with the story he grew too and it was beautifully executed. He learned a lot of things and by the end of the war he was much calmer and rational, able to understand the cosequences of his actions. So it really doesn't make sense that as an adult he can't control his outbursts when he should be very well aware how the public will react to it. It seems like a poor attempt at a joke by the author, but it just killed the seemingly well thought out journey he put Bakugo on.