What is the world coming to, when people hi-jack their own threads?
Changing rules: The only explanation I offer for this is what was wrong with the old, and how the new will be better.
Altering feats: If there was a legitimate mistake, and the player didn't understand what he was taking, or how it would affect him, I'm all for letting them change things. If there was RPing involved in the gaining of the original feat/selection, I won't change that, just provide something that fits better into the original concept. Even if that means giving a completely original feat that fits what occurred.
EG, if the player sought out some mentor in game to learn a feat, that would not change, but the nature of the feat might.