I am a newbie here... found this great post....and even though it is a bit old I like to add my 2 cents:
I am learning Scriabin's sonata #5 and Beethoven Appasionata. What I do is I learn a section from the exposition, analyze it with the piano (i.e. memorize the harmony, melodies, intervals, texture etc, play it on the piano and listen how it sounds). Then I go to the recapitulation, find the 'equivalent' passage, notice that it has been transposed by say a perfect 5th. So I transpose what I learned from the exposition upward a perfect 5th on the keyboard, without looking at the score - I need to do this extremely slowly since i am not good in transposition on the fly. Then I check my 'result' with what is composed on paper in the recap. I then realize there are lots of 'suprises' - such as a bar is dropped to intense the emotions, or notes has been added to intense the texture since it is a perfect 5th 'higher up' and sound 'thinner'.
When I practise, I practise 'equivalent' passages side by side - it makes sense to me since they usually are musically very similar if not exact. and they require the exact same technique. It becaomse extremely easy to memorize a piece - just memorize once in exposition and you almost have memorized the recapitulation.
Similarly I do the same with development section - again extract what was from Exposition and see how the composers developed that theme. then memorize the harmony, melodic alteration etc... right on keyboard. find out how he transposed or modulated, then transpose myself on keyboard and then check back what the composer wrote - again you would find lots of 'surprises'.
This makes me find learning a piece extremely interesting - as if I am entering into the composer's mind and compose togetehr with him.
Of course you should only do this if you are in no rush to learn a piece - because you would be spending time analysing and transposing, and rechecking. But once I learned the piece, I would not just have the piece "learned in the fingers", but I can explain pretty much every note in the composition - why the composers wrote that way. and can identify any nuances in the composition.