The lack of a full order breakdown within the individual order view. Specifically, the following details are missing:

Quantities ordered per item/product

Subtotals per item

Shipping fees

Discounts or coupons applied

Final totals breakdown (e.g. tax)

In comparison, apps such as Woocer and the official WooCommerce app display these details directly within the order screen, which makes order fulfilment and verification much faster