Sure, if you like.
The Lawbreaker stunts have te great and sigular advantage of actually portraying how breaking the Laws more than once or twice directly leads to inevitable Warlockdom.
But if you want to reflect that with mandatory Aspect changes instead, that should work out fine, though for most games you'll need something in the way of guidelines to decide when a character has gone so far they need to be made an NPC, but those aren't especially hard to come up with.
One of the major issues I have with them is that from a purely role playing standpoint, a player who wants to have a shady past (maybe a 3rd lawbreaker like Molly), has to start off with this penalty to their character's mechanical power. This can cause difficulty within the party balance, Players A, B and C are going to have more points to put towards their goals than Player D who has the lawbreaker. That means if Player C and D are both spell casters player C will invariably be stronger than Player D. Also, I hate that you get a "bonus" that you are discouraged from using.
Ah! I actually have an alternate way to handle this issue: I allow the Lawbreaker bonus to apply to two things other than breaking the Law (and in both cases the character in no way suffers for it):
1. I apply it to doing things that would break the Law but don't due to a technicality. I'd give Harry his Lawbreaker bonus to killing Ghouls and vampires with magic, for instance, or a reformed necromancer his bonus to raising an animal zombie.
2. I also apply the bonus to figuring out what other people with the same Lawbreaker stunt are likely to do. There's an incident in Turn Coat that sums this up best...
In both cases, you're that kind of person, and that means something.
