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1: I bought the score last week the moment it came out on iTunes - can agree with some of what you say, but can disagree with some too. The Batman riff/sound/whatever-you-call-it is iconic, and will be something that is forever, and immediately, connected with the trilogy. Same goes for the ever-rising chilling string riff for the Joker in TDK. 'Despair' on the Rises score I think was when Wayne was trying to escape Bane's pit - there are some low-volume minor-chord Batman sounds suggesting pain, and failure, and - well - despair, as the title suggests, then there is a long (but not too long) major-chord build to the same sound suggesting majesty and power. That said, 'Mind If I Cut In?' on the score, which is new and original to this film in the trilogy is a very simple piano melody, yet very haunting and very beautiful.
2: I was nearly hoping that Batman or Wayne or even both would be killed because I could see no other way the story could properly and conclusively end. For the last 45 minutes of the film there was always a niggling idea in the back of my own mind that the bomb MAY just go off and destroy a part of Gotham and all the characters we had fell in love with in the last 7 years of our lives. Nolan said the theme of Rises was pain, and what could have been a more painful and devestating finish to the trilogy than that? We would've been walking out of the cinemas like zombies, empty and speechless.
1: About the soundtrack. I pay a lot of attention to the soundtrack of movies, and while the soundtrack for the 2nd movie wasn't really what you'd listen to on your own, it had a perfect fit with the movie. From the very start of the movie, it sets the tone for the entire thing. Throughout the movie, the soundtrack enforces tension when needed, and goes into a more dramatic score, when Batman is leaving at the end. It does all these things perfectly.
The score for the 3rd movie, does reuse the "A Dark Knight" theme from the 2nd movie whenever we see Batman appearing in some amazing fashion (like when he emerges from the alley in the "Bat". And it does fit the character and franchise very well. Then there's the interesting theme when he tries to climb out of the pit, which is completely ruined by being way too loud. It actually became incomprehensible.
If I recall right, there was also a violin theme, which tried to enforce the tension in a scene (I think it might have been when he did the last and succesfull jump, when attempting to climb out of the pit). This theme was just dreadful. The track was obscenely loud and intrusive, and actually managed to take over what was happening on the screen (if that makes any sense). Obviously, I'm not very good at explaning these things, but overall, I'd say that the score for the 3rd movie, suffered from an extreme case of being incomprehensible and was without any real sense of directions.
2: The ending really had me shaking my head in disbelief. Was a happy ending like that really neccesary? I mean, him dying in a nuclear blast out at sea (how the hell did he manage to get that far out?) would've been lame too. But not quite as silly as him sitting at a diner... I do think a death would've been more appropriate.
You mention that we were at risk of losing characters that we've known for quite some time now, but how many of them did we really know? Aside from Bruce, Alfred, Gordon and Fox, did we know anyone else from previous movies?
I like Alfred. In fact, he was the only character I felt displayed any kind of emotion in the movie. But I'm amazed at how little he's in it. I can't help but wonder what he was doing during the occupation of Gotham? Fox also has a very small role and he hardly had anything interesting to do. Gordon was great in the 2nd movie, but I just didn't care about him in this one. He just seemed so indifferent about the whole thing. Where was the emotion?
And then there's of course Bruce. There was HUGE potential here with the way his character had developed. But once again, I don't see how they used any of it. This is mostly due to the dialogue he's given. No substance.
As for the new characters. Well, Catwoman really wasn't very interesting. We learned very little about her, and overall, she seemed more like a plot device, rather than an important character. Her romance with Bruce/Batman also felt forced. Blake was very likeable, but was also the victim of bad dialogue.
As already mentioned, Bane could've been very interesting. But they don't use him that much. His character is very restricted in the number of way he can express himself, as we can only see his eyes. His voice is kind of unique, though I still can't decide whether I liked the voice, or hated it. Only time I felt Bane was truely intimidating, was when he talked and finally killed the rich guy who thought he could use Bane to accomplish his own goals (The guy who wanted to take over Wayne Enterprises).
And last we have the real villain. But what do we actually know about her? I'm assuming her whole "save the world by clean energy" thing, was just an act. So what we're left with, is that she's consummed with hatred. The whole "Give Gotham back to the people" had zero point. In fact, why did they even do that? It obviously wasn't the main objective, and even if it was, it would've been left mute by the fact that the nuke goes off no matter what.
I wanted to like this movie so much. Which is why I was bordering on actually being angry when I got out of the theater. The depth and intelligence seen in the 2nd movie, just wasn't here.
Sorry for the long read guys. I got carried away.
And number five is on Saturday afternoon. After last night, any question or doubt I had was answered easily - even the stuff on any other forum or article I had read. Even the 'how did Batman survive the blast' question. Actually, a very simple answer when you know what to look for on the screen 
