getting on this thread late and have not read all replies, so...
I view PrC as a DM's option, and the DM should look at them very carefully before allowing them into their game. They are an element for the campaign and what the DM is trying to develop with plots and campiagn, PrCs become pathway careers for the players. Does this curb creativity? Yes, for the players but no, for the DM, players take the roles the DM presents to them, on the other hand the DM is the director with a mission statement and scope.
I guess the debate comes down to who has the right of ownership of the character (DM or Player), the type of game and the type of players. Do players play the game and the DM run it, or Does the DM run the game and the players play in it?

I view PrC as a DM's option, and the DM should look at them very carefully before allowing them into their game. They are an element for the campaign and what the DM is trying to develop with plots and campiagn, PrCs become pathway careers for the players. Does this curb creativity? Yes, for the players but no, for the DM, players take the roles the DM presents to them, on the other hand the DM is the director with a mission statement and scope.
I guess the debate comes down to who has the right of ownership of the character (DM or Player), the type of game and the type of players. Do players play the game and the DM run it, or Does the DM run the game and the players play in it?