Duane Cole checked me out in a Citabria, and, in a very understated fashion, made most of the observations you all are making a priori (insofar as I was concerned).
He further taught me how to do a real barrel roll. (though I am still fairly convinced I never did one up to his standard). He insisted that this maneuver is not, in any way rate-dependent, and may be subject to arrest and inspection at any point during the rotation. Should such inspection be demanded when one is in an inappropriate power and control configuration (as, surprisingly, was invariably the case), the resulting flight condition changes are demonstrative of poor airmanship and, for the student, fairly embarrassing (to say the least).