The more I read of Rushdoony's Institutes of Biblical Law, the more insightful I find him, and the more off base in other areas. To borrow a phrase, sometimes he's on to something, and sometimes he's on something.
He notes that church and state both have a responsibility to kill and make alive: to punish sin and crime, and to provide charity and governance. If church or state only kills, it is tyranny. If they only make alive, they compromise truth by not judging against sin or crime. Great stuff.
Then in the following pages he advocates "total avoidance of... violations of 'kinds.'" (256). This means no hybrid plants or "futile experimentation, such as organ transplants, which represent sterile and limited gains" (262). Hm. Besides rejecting the Westminsterian categories of ritual or civil law as applying only to Israel, this denies some life-saving scientific gains (kidney and heart transplants!) which violate no biblical law.
Rushdoony makes an insightful connection in the kind category of not being unequally yoked, as applying to inter-religious marriage. But then he goes on to say, "The burden of the law is thus against inter-religious, inter-racial, and inter-cultural marriages" (257). He
But he insightfully connects the laws calling for kindness to animals to the sixth commandment. He goes on for several pages against pesticides in farming, which I'm not sure I agree with. But then hits some zingers home: "The myth that technology is the solution to all of our problems, however, is being questioned more an more" (259). "Man therefore must work in harmony with creation.... It is all the same a fallen world. To ascribe perfection to it, and to assume that the 'natural' way is the perfect way is not Christian but humanistic. Because the world is fallen, and the ground itself under a curse (Gen 3:17-18), what is natural is not therefore of necessity good (262)."
All in all, that's pretty balanced, I'd say. Work in harmony with creation, taking dominion, but the natural is not the standard.