He wanted to cram more stuff in one arc. It's understandable, and commendable. The story would've been better for it, if only he hadn't reduced to zero the SHs interactions to facilitate it. Cutting panels/skirmishes to get to the point of the arc would've been excusable in the long run; cutting on the SHs' individual importance and their ensemble interactions was the mistake that would've killed this series, had it not already been this massive.
I agree, the best moments (most remarkable) of the whole manga are born from the interaction of the main cast (extended to very important secondary characters Oda spent time to create great dynamics with): Ace's death, Luffy putting his hat on Nami at Arlong park, Robin's "I want to live", Zoro ready to die at Thriller bark, Luffy enraged at Kuma in Sabaody etc. etc. (they are also the core moments of their respective arcs, they summarize the whole arc and are its climax in a way).
Now Oda cut the main cast time by a lot (also we don't get the old gags which were great for comedic relief) but we have lots of secondary characters each arc, and by the end I don't even (care to) remember the names of most of them because they have almost no impact. If I have to pick great moments of the post time skip I would just take the minks revealing they hid Raizo, G4 announcement by Luffy at the end of a certain chapter (that hyped me a bit but mainly because the gears were built through the pre timeskip), maybe Sanji kicking Luffy face in WCI but thay was just fake tension since it got resolved cheaply... And that is it. I can't recall a moment like this for the whole Wano arc (4 years) and this says everything.