I think this is a terrible idea. Part variations matter for aesthetic and occasionally for performance purposes. As Logan said, there is already a category for buyers and sellers who didn’t care – “undetermined type”. This decision adds little value to the consumer and seriously disrupts hardcore users.
There is also the point Logan raised regarding set inventory. While one may argue that is not the primary purpose of Bricklink, it is a function that we as the community have come to expect from the site. Guess we’ll have to start buying original instructions to try to divine what actually came with a set.
Does Stud.io also ignore these mold variations?