This is a bit of a pain, we suffer the same issue in our applications. We already have all product details so we compare it to that, however I understand this is a bigger issue when this isn't available.
We find many applications cause this problem such as any application that offers tiered pricing. These applications delete and recreate variants all the time and break the connection to the original product.
+1 on adding something to identify this without needing to scan through all products.