the power of the queen compared to other pieces

Interesting question. The actual power of the Queen doesn't change but the player's view of its importance decreases a little as ratings increase. Larry Kaufman's celebrated study of over 80,000,000 chess positions in the 1990's determined, on average, a Q = 9.75, R = 5, B = N = 3.25, P = 1.
Lower rated players tend to be much less likely than higher rated players to trade a Queen for two Rooks or a Queen for Rook, Knight, and two Pawns, even though it's usually to their advantage to do so.