A lot of people think the opening is dribble, that to play the opening well is not only unimportant, but a waste of time. I will tell you this: if you delay chess thought till the middlegame, you will always lose to a person who has spent time on their openings and is prepared to play the middlegame and endgames intuitively. How you open is so important to where your game goes and many people don't realize this.
I know a former IM strength player (He's older now, and dropped to 2200) who has given me much advice and helper me improve my game, and what he always told me was;
"Studying openings is like memorizing the phonebook"
While studying openings IS important, I have done quite well by simply knowing and studying middlegame concepts. The best idea is, IMHO, to study a few openings you really need to know, a few sidelines, and mostly learn how to play the middle game.
If you read the soltis book on pieces and their relative strengths, you'll realize that the strengths of the pieces are an illusion relative to the endgame.
What exactly do you mean by that? And what exactly are shifting power levels?