I tried all the settings. with and without hard crop, and also leaving blank alternatively width and height with and without hard crop.
Of course I regenerate the thumbnails at every change of settings. After one hour of trying I asked for help in this forum :-).
I am not so expert in coding to understand if this behavior is produced from Woo core or from the template. I begin to think is an issue depending from woo, which does not gives any possibilities to fit the image to the desired dimension, but only gives the option to crop.
So if you have an img 200 x 500 and another one 500 x 200 you never have the possibility to get them in a 200×200 place, proportionally resized without crop.