Although I've been to many Federalist Society events, I have never seen this issue discussed: Do heightened pleading standards violate separation of powers principles? Why do you think that is? Could it be that people who decry "judicial activism" don't care about activism qua activism - but instead are merely upset at the results of controversial cases? Perhaps Ninth Circuit Court of Appeals Judge Stephen Reinhardt was right, after all? See Judge Stephen Reinhardt's Footnote Five.
In our system of separated powers, judges are to interpret the law. The Federalist Society's favorite quote from the Federalist Papers reads: "The courts must declare the sense of the law; and if they should be disposed to exercise WILL instead of JUDGMENT, the consequence would equally be the substitution of their pleasure to that of the legislative body." The Federalist No. 79(Alexander Hamilton) (concerning the judiciary).