In its current form, while technically functional, the built in editor for modifying product variants is a dog's breakfast.
The amount of wait time between clicks to go between the general product editor page and the variant page is time-consuming and arduous. My largest product has 90 variants. If you have to perform an update to all of the variants, you spend half your time going back and forth double checking that you didn't miss one along the way, as there's no indication at the top level to show which one's you've updated vs the ones you haven't. But more significant is just the amount of unnecessary mouse-clicking and waiting for the screen animations to slide the page in and out (which some might find aesthetically pleasing, but I find to be unnecessarily time consuming). Of course adding to the amount of time is the amount of sighing, eye-rolling, and cursing along the way when you find yourself aggravated by the fact that something that should only take a few minutes ends up consuming an hour and a half or two hours of your life that you'll never get back.
Someday I would love to see some sort of single screen grid layout so you can rapidly make these changes across multiple variants quickly in minutes. Or alternatively be able to automatically open up all the variants in Zoho Sheet similar to the way I can perform mass edits in CRM can do with nearly any one of its data types - although without the 100 record limitation in CRM. (Add to that tax areas, shipping zones, etc.)
Due to these factors, I've pretty much just written off using the product editor for variants almost entirely, and instead just export everything to a spreadsheet, make the edits, and reimport. Not the end of the world, but tolerable, and it works in most cases these days.
Except in one case... Variant level photo selection/manipulation.
It was nice to see that the URL for variant images as part of the export file in Commerce, making it easy to export the URLs to shipping software, or for any other reason.
Why was this not also included as an available field on the import?
I should emphasize that I'm not talking about importing the actual photos themselves. I get that that's another whole can of worms. And for my purposes at least, I'm fine with the fact that you might not be able to directly import product photos (although there should be a means to make this happen from Google Drive or Workdrive, or some other location on the web, just as the Amazon interface does).
What I'm talking about is if you already have photos uploaded into a product, you should be able to determine which of those photos are presented for any variant by some means by way of an import.
And so while I'd like to hold out some hope that someday a grid-style or spreadsheet style editor for product variants will eventually be a part of Commerce, permitting the import of the URLs for existing variant photos (in the same manner as presented in the export) would be enormously beneficial, and alleviate the burden of going into every variant for something as trivial as changing or adding or deleting a photo across an entire product.