I don't think it is a must have feature - especially in a game where you can't easily completely mispec yourself. For me an RPG always meant you have to live with your choices, including on your character.
This being said, I don't mind the feature too much. But as stated it is really too cheap, especially late in the game. Right now if you want to scribe wizard scrolls it is cheaper to switch specs a few times for the 50% price reduction.
