If they also made blocking not take up vigor and instead just have you take chip damage, you got yourself a deal.
Only certain skills have a slot on your skill tree to allow you to add a mutagen. Just highlight a skill that you added and has an empty circle on the top part of the icon and press Y if using a pad and you can select a mutagen.
The prices are 24:1, so I would suggest just modding it so that's back to Witcher 1 scale of 5:1
http://www.witchernexus.com/downloads/file.php?id=67
24:1...why?
