There are two visions on what to send.
A. Send a picture from which a buyer can make as much as possible (keep opportunities to use it open). In this vision you best send the not-cropped.
B. Send the picture ready to use. Than the cropped is better. It is in the way it will be used most probably.
Whatever is said theoretical.... In microstock the practice is vision 2. The cropped is more of interest and has the best composition. I consider the uncropped even has the risk to become denied because of that.
I'm sorry to have to say...microstock is mostly about easy, cheap and quick...and not about much considerention and great visions.