Wow, I haven't written any posts in this forum in years, but I guess this is as good time to start as ever.
I actually really liked the conclusion of this chapter. It was the Jaya scene recreated but with completely different emotions behind it.
Luffy's one-hit KO was extremely satisfying to see at Jaya, with Bellamy being an annoying and cocky jerk who thought he knew how the world works and everyone who thought otherwise was an idiot, but Luffy broke all that with one punch. And I loved it, because Bellamy annoyed and frustrated me like no other antagonist before him. Now that I think about it, it's probably because I know people like him exist in real life: they live in their own little bubble, mock everyone who thinks differently than them, seem to be uneffected by all kinds of reasoning, and sometimes you just want to punch them to pop their bubble.
I guess Luffy managed to do that, since Bellamy changed. Sure, Oda could have conveyed some of Bellamy's development in a better way: I sometimes felt sympathy for him and sometimes though he was a bit too pathetic. But I like that he clearly had become more understanding of other people, and Luffy noticed that too. Luffy even started to consider him a friend. But Bellamy still kept clinging to Doflamingo, and this eventually forced Bellamy and Luffy to fight again. This time, Luffy did not want to hit Bellamy. I think it's totally in character for him to get so angry that Doflamingo basically forced him to hurt a friend. At the same time, Bellamy was even more desperate than usual. He actually looked like he wanted Luffy to beat him again, so he could maybe finally get enough sense into his head and let go of his wrong idol.
And that's what made me really like the throwback to Jaya: it showed that while the power-relations between Luffy and Bellamy hadn't changed, everything else had. Now the punch was something that Luffy didn't want to do. Bellamy understood that Luffy was completely capable of doing that, and when he finally did, Bellamy was actually thankful for it.
I understand that not everyone liked it, since the fight didn't have much focus, but for me the conclusion was actually very powerful. I think that as a whole, Bellamy's character arc has been a very nice one. Of course he's not dead, but I don't think it makes the scene any weaker. I think Oda's words in vol 4's SBS fit very well:
"In this era, people put their lives on their beliefs and convictions, and fight. When he goes into battle, Luffy is destroying others' beliefs. And when these enemies' beliefs are shattered and defeated, they feel a pain equal to death."