I think you exaggerate a bit when you claim the english common law was rejected wholesale. I am no scholar on the matter, but ISTR that Justice Holmes wrote a study on the provenance of laws, tracing many to the English common law.

Well, I dunno. Propose a measure for what counts as “rejected wholesale” and I’ll tell you what I think. But we rejected the notion of the Divine Right of Kings and replaced it with government by the consent of the governed; we rejected a notion of a “constitution” that vaguely sets out some historical arguments about differences in responsibilities and replaced it with a written Constitution that set out the powers of the Government explicitly and great care taken to be rigorous and complete; and we largely rejected the common law — which is, remember, the accumulation of precedent without written statements of the law itself, cf. Blackstone — in favor of an explicit written code of law that was considered determinative and more or less final.

I count that as “rejected wholesale”, but your mileage may well vary.