And that's my broadened version. The version that gives +1 control only to kill humans specifically? Absurdly and unconscionably weak for a full Refresh. Heck, that's weak for a Stunt, never mind a Power. A Stunt to give +1 to hit humans with an attack skill is plausible...but add the killing restriction and that's weaker even than most other Stunts. And Powers are rather intentionally more impressive than Stunts.
It can be useful at high Refresh. The pyramid system puts a premium on cap-breaking bonuses.
But yeah, it's pretty terrible at the levels people are actually meant to play at.
I'd say that the problem I was worrying about was more that they'd add a few more Lawbreaker powers. Then they have a +2 or +3 to any attack they make, so long as they're aiming to kill.
That is extremely expensive refresh-wise and not really worth it unless you're having cap issues.
Do you have any suggestions for Lawbreaker (2nd-4th, & 6th)?
The second could probably be stretched to include a variety of maneuvers. Evocation can't really transform people but it can put Aspects on them and if you squint that's similar.
The fourth is powerful if you allow mental evocation attacks, which Evil Hat seems to. You shouldn't, though.
The third and sixth, unfortunately, are pretty useless for evocation and pretty narrow for thaumaturgy. You could have them broaden the Lawbreaker's evocation a bit; perhaps Sixth Lawbreakers can use time as an evocation element.
Might be worth thinking about compressing multiple Laws into single powers. You could connect them all to the same Power, or just merge 3+4 and 6+7.
I'm pretty sure this problem has a built-in solution: the stronger they are, the more likely they are to get killed by the White Council. Players abusing Lawbreaker powers? Throw a warden hunting party at them. They dodge that? Well, whatever problem they're trying to solve has also attracted the attention of the White Council. They kill the wardens sent after them? Well, now they've attracted the attention of Blackstaff McCoy, and so on.
The solution to a player taking over the story by being stronger than the other PCs is not to have them take over the story even more.
Besides, Compels are supposed to make things like "somebody wants me dead" into mixed blessings rather than outright problems.