Technique can be more interestingly found in playing pieces.
Very often, pieces as such distract the player from finding very simple but quite essential secrets the instrument can reveal to you by taking another approach. For example: how many thousands of pieces does one have to play to realize that if you "mirror" the hands in major scales (symmetric inversion), you get this:
C (-) from I to I (=Ionian) -> = C (-) From III to III (=Phrygian)
G (1#) from I to I (=Ionian) -> F (1b) From III to III (=Phrygian)
D (2#) from I to I (=Ionian) -> Bb (2b) From III to III (=Phrygian)
A (3#) from I to I (=Ionian) -> Eb (3b) From III to III (=Phrygian)
E (4#) from I to I (=Ionian) -> Ab (4b) From III to III (=Phrygian)
B (5#) from I to I (=Ionian) -> Db (5b) From III to III (=Phrygian)
F# (6#) from I to I (=Ionian) -> Gb (6b) From III to III (=Phrygian)
F (1b) from I to I (=Ionian) -> G (1#) From III to III (=Phrygian)
Bb (2b) from I to I (=Ionian) -> D (2#) From III to III (=Phrygian)
Eb (3b) from I to I (=Ionian) -> A (3#) From III to III (=Phrygian)
Ab (4b) from I to I (=Ionian) -> E (4#) From III to III (=Phrygian)
Db (5b) from I to I (=Ionian) -> B (5#) From III to III (=Phrygian)
Gb (6b) from I to I (=Ionian) -> F# (6#) From III to III (=Phrygian)
This works both ways, so you can use one hand to solve technical problems in the other one in unexpected ways. One may also find out in this way how illogical the traditional fingerings for scales actually are. Minor scales have their own simple "regularities" and so do triads, chords, etc. Is this all really "a waste of time"? I'd say it's an incredible leap forward in understanding transcendental technique, much more effective than simply repeating pieces until you know them and until you have practised all the life out of them.
