Forget everything about the metaphysical part of the Laws for a moment and think about it this way;
1) Invading minds is forcing yourself into a person's most intimate parts without consent. Getting information from someone forcibly is like beating them up until they tell you. Changing people's minds forcibly is like lobotomizing them or doing shock therapy until you get the desired outcome.
1b) Believing that rape, torture and mutilation makes you what you are (wizard or otherwise) means you're dangerously, undeniably insane. Lawbreaker ahoy.
2) Transforming someone into less than human (such as a pig ala Circe) by force means a) they no longer have usable hands or upright position, b) they no longer have free will, c) they no longer are intelligent at the same level since they don't have a human brain.
2b) Believing that slavery and mutilation makes you what you are (wizard or otherwise) means you're dangerously, undeniably insane. Lawbreaker ahoy.
3)
if you agree that the rules hamper the fun of playing a wizard
Nope. The rules say that if you are a dangerous, undeniably insane guy with access to the equivalent of high explosives or worse and like to use them one of the following applies;
a) You've become dangerously insane on some level. If your stability of personality and free will (refresh) was not good to begin with (only had 1 point left) then you lose it and become a monster.
b) Dude, you're dangerously insane and have access to high explosives that cannot be taken from you. Even if you didn't degenerate into a total monster, the wizard secret police (and any police) will totally try to shorten you by a head.
3b) If you're having fun lobotomizing, mutilating and raping people, then chances are you already have Lawbreaker and don't know it. Better add it to your sheet - you might as well get the benefits along with all the negatives you have anyway.
4) Dresden is insane at some level. He recognizes it himself. It is even metaphysically confirmed multiple times in the series. That's not
only because he broke some Laws but it did play a part. A big one.