Musicman, I do not really agree what you say. But anyway, everyone is entitled to their opinions. One thing you have to note is that more hours spent on the piano DOES NOT EQUAL that you will have quality time practicing. I do practice 6 hours a day, but not many people have the luxury of doing that because of working or study commitments. The more realistic amount of time people will spend on piano will be 1-3 hours per day. Its not the amount of hour that counts , but its what you do during the hours that count. You mention you practice 5 pieces everyday, anyway, I don't believe in practicing too many pieces at once. All the concert pianists I met so far, including my teacher, practice at maximum only 1 or 2 pieces one day, and the rest of the completed pieces for their performances they will go through only once or twice everyday.
Focus is extremely important in pieces, only by focusing you can focus maximum music making. By having a lot of time devoted solely to a single piece, you will have ample amount of time to analyse and 'feel' the piece you are practicing, and also doing your homework on the background of the music helps a lot, and also, never ever continue practicing a piece more than one week without guidance of a teacher; if you have musical and technical errors, they will be harder to erase.
I have followed this method of practice , with music making my aim priority. Many people seem to forget this in practice, their goals is just to play as many notes as possible, but frankly speaking, sounds really horrible.
Believe, 1-3 of practice hours spend wisely making music is much more rewarding that 6 hours of continuous practice trying just to master the notes.
Cheers