It should show the price, but yeah, all of the item details would go away. Did you continue and return back to the review page on your site? The pricing would be broken down there, and then the final call would submit the pricing to PayPal.
On that note, we need to make the same adjustment to that final call. So I would have you do the same thing on lines 1769 and 1788...comment those out.
With those changes, completing the full order should result in the order amount and order ID getting sent to PayPal correctly, but then you'd have to refer to the WC order to see the actual items.