The boat chase is insipid in execution, but not extraneous. I think it’s a perfect situation for an action sequence. Bond is completely clueless. He’s essentially blind to everything around him, holding on to his one and only lead, that being Camille. He follows. To expedite the story, we are presented with Camille’s situation and see her get passed to Medrano as a piece of entertainment.Well, the infiltration in Hong Kong was extraneous, and I've said as much before in commentary on THE DARK KNIGHT. It was one area in THE DARK KNIGHT where things should have been streamlined. But it's certainly no more extraneous than QUANTUM OF SOLACE's boat chase or plane chase, and, I'll add, it's far more entertaining than either.
But the two biggies I'm thinking about are the vehicle chase, which is definitely THE DARK KNIGHT's biggest affair, and the finale with the Joker. You've already expressed your distaste for the latter, and I won't bother arguing about it, but I'm sure you remember enough about it to know what's at stake there narratively speaking. But as for the vehicle chase, you have the Joker trying to kill Harvey Dent (who's pretending to be Batman), and Batman trying to protect Dent and get the Joker. So it's really all about the characters, and eventually it boils down to just Batman/Joker in that wonderful showdown.
It makes complete sense for Bond to go after Camille, being who he is, and since Medrano is not likely just to hand her over, it results in an action sequence.
I’m with you that the sequence is for the most part dull, and ends inexplicably, but I don’t agree that it is unnecessary.
The plane sequence is much less necessary narrative-wise, and in that regard can feel a contrived. After all, we HAVE to get Bond into a sinkhole somehow, and we HAVE to have an action sequence which takes place in air, being one of the four elements, so… <snap!> A dive from an airplane!
But I’m on the up and up with how it works in execution. I think it’s a thrill. I’m in agreement with Hilde’s post above. If it’s DAD, it’s DAD perfected. Even better if that was the actually intent, and I wouldn’t be surprised to find it was.
As for the Bat-Maannn… I will certainly give him another chance. And this time, I will be looking at particulars.