Your other thread did go fairly off-track.. partly my fault, sorry about that.
I don't feel that czerny/hanon is a waste of time, just that as j_menz delicately pointed out, there are better ways to learn the exact same things.
Scales on the other hand are completely invaluable as far as I'm concerned, and can be practiced in advanced patterns that make them not only valuable technically but theoretically and musically as well.
the traditional 4 octaves up and down, while perhaps a reasonable technical starting point does not constitute what I would consider good scale practice for someone at your level. As even the most basic starting point for something more useful I would consider playing something along the lines of LH plays the arpeggio in quavers, RH plays the scale in semiquavers for the ascent, swap for the decent.
...or, play a scale ascending and descending in a pattern such as 13243546 (scale degrees) - change key every few notes following a progression such as the cycle of 5ths, alternating between major and minor. - i'm just making this stuff up, create your own idea that sounds good to you.