There are a couple of things that would improve the usefulness of shipping.
 
1) Surcharge. For many vendors, some items they sell incur oversize or special packaging surcharges. For instance, shipping unboxed items, like a tire or a long mailing tube, will cost a shipper an additional $7.50/item when using most carriers. It would be great to have a packaging surcharge field in the product database.
 
2) Markup/Markdown. Most real-time systems return standard desk rates. Most shippers have some form of discount from these rates, in the case of UPS and FEDEX the discount could be as high as 65% off published rates. It would be great if each shipping method had a discount multiplier so a vendor can pass along discounted rates to their clients. As is, any high volume shipper has create a complicated zone based implementation to get accurate shipping rates.
 
3) Default shipping. Administrators should be able to select a default shipping option that is checked off at checkout. THe admin should be able to set a default for each country and state. The current implementation almost makes the user go throung an "ooops loop" in most cases (ooops loops are one of the biggest factors in abandons).

Excellent idea.

as far as im concerned, I love the shopping car however I really dislike the checkout. it should be much less annoying. if customer doesn't have default shipping info, then they have to fill it in. once they click on the country, the page refreshes. then they have to scroll up and pick the shipping method. maybe put it on the payment page or creat a java script that will not require auto refreshing the entire page, but something needs to be done.