The terminology 'reversible flight control systems' might be an engineering term, but is used e.g. in this paper from the USAF test pilot school:
https://apps.dtic.mil/sti/tr/pdf/ADA319984.pdf And no, my question is not related to the concept of manual reversion. That is quite clear and without hydraulics, the flight control system of the 737 is reversible (for pitch and roll) - as I also outlined above.
My question really relates only to the "normal ops" condition where hydraulics are powered.
E.g. would you be able to 'feel' ice build-up on the aileron / elevator on the yoke provided the control surface isn't jammed? So a situation similar to American Eagle flight 4184 where ice build-up led to unexpected aileron hinge moment reversal that moved the aileron (and in return also the control wheel),
The ATR72 as in that case does have a reversible flight control system but I'm wondering how this would play out on the 737 (in theory). I believe with newer designs of non-FBW aircraft such as the 747,757,767,A310 this wouldn't be the case, since the flight control surfaces are indirectly actuated by PCUs.
But as we know, the 737 is a little 'special' here.