A Nolan film's themes could be written on a napkin as far as I'm concerned. Storytelling as wish-fulfillment, basically. What the protagonist in Memento demonstrated is that people need their lies in order to live their lives. Batman is deceived about Rachel's intentions, Gotham is deceived about Batman -- all for the greater good, so people can be better people. Inception asks whether living in your dreams is preferable to reality, skewed by that last scene so the question becomes whether films are preferable as well. The Prestige is about filmmaking (as a friend of mine told me a long while ago). The three parts of a trick are like the three acts of a movie -- set-up to deliver audience satisfaction. Such manipulation is addictive -- one does it for the roar of the crowd, the other for the ingenuity of the thing itself. Both leave destruction in their wake. While the rivals look to uncover each other's secrets, Sarah wants the truth that really matters. As Inception suggests to the audience at the end -- family is better than all the dreams you can invent.
The Nolans' ideas are interesting, sure, but they do tend to make characters into props. Moreover, the tight control over the plot, the economical script, the utilitarian cinematography, fail to dazzle or astound me. The Nolans are mechanics that build ingenious storytelling machines, and however good their actors are, they never blast through the complex contraptions that surround them.
There is one exception, The Dark Knight, which I watched again not too long ago and am still wowed by. Others found the indulgence the Nolans allowed themselves to be a weakness. For me, the improbable scenarios building to ever more improbable scenarios created a kind of operatic swell that no other Nolan movie can match. It is the feeling of Heath Ledger's magisterial Joker asserting his will over Gotham, an entire city enraptured and terrified by this sinister charismatic presence, that goes down as their supreme achievement. And I have my doubts about whether The Dark Knight Rises will be able to match it.