Why have they arranged portkeys for everyone else? Harry needs it, but everyone else can apparate. It seems a little silly. Yes, I can see the value as a device to heighten the suspense and suggest that something horrible has happened to them because they did not arrive on time, but it does not work within the plot. Much like including Mundungus in the plan to save Harry -- there must be better candidates available. Rowling's writing improves, but sometimes she gets carried away by devices which she does not bother to back up.

Lupin assumes the person who betrayed them did not know there would be seven Harrys (Harries?), but Snape must have known (if I recall correctly, he was the one to suggest it to Mundungus). Just sayin'. The same goes for cursing George's ear. It sounds bad, but it really isn't.

I like very much that Dumbledore told Lupin and Kingsley to trust Harry. And that Harry gets to know that he told them. It makes me warm and fuzzy inside.

We've discussed how the war is real before, but the sequence of deaths and near-deaths in the move from Privet Drive is what really makes it clear to me that at this point Rowling has no incentive to keep anyone alive anymore.

The wand problem shows up. Both in that Harry's wand acts of its own accord, and through the vision revealing that this is despite the fact that Voldemort has taken the precaution of using Lucius' wand. Do we ever get a satisfactory explanation of this? Is it down to the horcrux in Harry?

We also learn of Mad-Eye's precautions against Snape at Grimmaud Place.

And we learn of the use of remorse to heal a splintered soul, as something excruciatingly painful -- which we'll see towards the end of the book in Snape's memories.