Hey folks! Good question! I like that discussion. As I can see, lots of people believe in magical touch of technical exercises. You know, I do to!
Coming from the Russian school (mentioned before) with all this early traning, I had to do lots of scales: major+3 minors straight and combined-opposite, parallel tercia, decima, sexta; triads with inversions (3- and 4- notes), 3 kinds of arpegio (straight, broken, long), D7 (dominantseptaccords), diminished 7, and in the end chromatic straight and opposite (least favorite ones except D or G#, you know why). And of course, from every key in 4 octaves up-down.
I remember myself sitting at the piano by hours and practicing THOSE scales, having technical scales exams every month. Oh, forgot about tons of etudes I got to study - like the whole Karl Cherny, Duvernoy, Schitte, etc.
My point is: you hate it when you actually play it (I was crying at opposite chromatic quite often), but it makes you hands feel so good and powerful when you passed a lot! Now, when I had like 11 years of everyday hard training, it doesn't take me a long time to pass difficult technical moment, because my hands-shoulders-elbows-fingers, etc. are completely prepared for it! It's like being an athlete - you trained your muscles, it stays with you forewer: even if you didn't practice for a while, once you catch up and get in shape (it only takes several days, believe me) - and you are up again, ready and powerful! That's why I can play Rachmaninov or Beethoven...
I don't know, but I really admire my piano teacher (thank you, Lioudmila Yurievna) who made me go through all this scales-etudes stuff and encurage me to practice hard! I would really recommend technical exercises for everybody, that's my opinion (sorry for the ong post).