I've just started uploading my first items and there are 3 things that stand out to me most and would make a huge impact.
1. Items should be able to sort by SKU/Part # or Name, not just name. Otherwise it forces me to use valuable description characters to include the part number first, then the description.
1.1 Adding a thumbnail of the icon/color/image to the item list page would make it easier to know if the image was imported or not and visually move through the list instead of opening each item.
2. It would save a ton of time to be able to import the photos and have them mapped in another column on the import sheet. For example, column U could be "Image" and the name of the file could be placed here. Then with a new import dialogue window multiple files could be uploaded at once. Import the images first, then upload the item list to find the images.
3. Category Images - First, they need the capability to have an image, then there should be the same import dialogue for category list as there is for items, again mapping the image.
Obviously 2 and 3 would take quite a bit of coding, but adding a category image until then should be an easy fix until they can be fully implemented.