I don't think mining metrics itself is a bad thing. As a player of primarily online competitive games like Counter-Strike or SCII, there are certain metrics that I want devs to keep track of, like average game length, which units/guns/etc. are used most commonly (may indicate an issue with game balance). I think data about the game is useful to the devs and ultimately the players, since it can influence improvements to the gameplay experience. I'm sure that the data being kept by many F2P games is well beyond what I would consider acceptable or necessary, though.