@Jurgen8e: Your request for taxonomy filters makes sense, I'll try to implement it in the release for UC2.x. The "product identification" works through the SKU, so changes during you use the stock editor isn't a good idea. You should reload the stockedit page if you meanwhile added or changed products or SKUs.
@stilln: Need more information. Which other stock related contribs do you use? Attributes? Anyway I am pretty sure that all products are shown. What might confuse you is that ordering is still by SKU only. The UC2.x release might get more flexible.
If all products are accessible you can easily control by going to /products and override this view. Change the page view to display 30 products per page, under Fields add "Product: SKU", Sort Criteria also add "Product: SKU" and move it to the top. Save and go to the last page. You should see that the list ends with the same product like stockedit.