Some more Dressrosa thoughts (I guess I'll spoil these??):
People here mentioned the pacing, and yeah, I can definitely see how reading this week-to-week could be a bit exhausting. ESPECIALLY the fakeout Luffy win over Doflamingo, leading to the whole "stall for ten mintues" section. That felt a lot like padding, though there were some neat moments (i liked seeing all the different groups trying to stop the birdcage from collapsing)
Obviously, there's a lot of parallels between this arc and Alabasta. I'm not even sure I have to spell it out... if you combine this with Punk Hazard, this whole segment of the manga feels like the first major arc of part 2, just like how one could argue Alabasta was the first major arc of part 1. This isn't a criticism or anything, just something I pondered while going through Dressrosa.
Gear 4... I always thought it looked goofy, and it is. But, you know, I think it works? I like that this form isn't traditionally badass like a lot of other shonen protag's transformations. You can tell Luffy is serious while using it, but it doesn't lose that silly/comedic charm that he's got going on either. I also like some of the body-horror-adjacent things like the fact that Luffiy is now so rubbery he can't stop bouncing, and now he can retract his hand into his arm like an arm cannon.
This was also Law's big breakout story arc. I know he's a popular character, and I can see why. Though personally... when it comes to the Worst Generation, I kinda like Captain Kidd a little more still. I think it might his powers, I don't know
Speaking of padding, I was not into the coliseum stuff at all at first. But I think it lead to a really nice payoff, by spending all that time there, it made the gladiators' eventual alliance with Luffy even stronger. I loved that they all decided to pitch in and help when Doflamingo lowered the birdcage
And speaking of alliances... as soon as the gladiators proposed becoming a Straw Hat alliance, I KNEW Luffy would refuse. But I loved their response, since they're all free people that can still just willingly choose to align with Luffy without it being a official thing
Bartolomeo is probably the fastest I went from hating a character to liking them. Their straw hat fanboy schtick really works for me!