Indeed legacy poses with y-rotation of the hip need fixing. One of the things on my little list of PE helpers. A script reading the hip y-rotation, setting it to 0.0, and apply rotation previously for hip-y-rot to the body dial for hip rotation, something like that. I found legacy poses also having 'baked' joint translations in the fingers. It is only a few mm, but it makes the hands look ugly. Sure these offsets were necessary at the time the pose was made to compensate for the flaws but modern figures do this automatically so the effect is doubled. Resetting dials for joint translation to 0.0 would be another script task. Finally, for V4 based poses, to compensate for the arm bend and finger bend.

I agree about adding your own touches, but I prefer to keep these restricted to actors not higher in the hierarchy than collars and thighs.