I don't think that it's worth it. It gives +1 to control only, while a level of Refinement gives two +1s to distibute as you wish.
Lawbreaker might be useful if you intend to violate a given law with multiple elements and thaumaturgical fields, though. It really depends on which Law and the circumstances. Seventh Lawbreaker could be pretty good for a character with Sponsored Magic (Outsiders), while Sixth Lawbreaker will very rarely matter.
PS: Disregard the above if you have enough refresh that the magical specialization pyramid is actually giving you trouble.