Here is something that bothers me a little bit. Let's say I am creating a new product, fill in all the fields, carefully write descriptions, add photos and stock amounts... and then reach the options section. Now I want to add a new option using "Available options" > "Add option type".
But when the option type editor opens in modal, all unsaved product data is erased, and I have to start all over again. This is extremely frustrating, even though you learn it quite fast after it happens once or twice. Still, I can already imagine this is something that would cause a lot of negative feedback from customers (=my agency customers, the merchants) who are using their new store for the first time.
Therefore I suggest that the product changes are auto-saved when "Add option type" button is pressed, or a message is shown "Do you want to save changes? Yes or no" or something.