Featured image and product gallery on same meta box
Creating a different meta box for product galleries was definitely needed, but I feel like this is not quite the optimal solution.
Featured images and product galleries are usually added together when creating a product, therefore we need to put them into the same meta box.
Just like any other shopping cart, the first image must be automatically set as the featured image and the following added to the gallery, with an option to reorder, delete or set as featured.
At least an easier way to "move" a photo from the gallery to the featured image and vice versa would be nice. It is quite difficult to do this on a store with over 16,000 images.