IMO (and it's just my O, being not in the US, and therefore knowing little about it), if you are going to declare yourself a nation, then a standard letter should be a standard price, regardless of where in the nation it is sent, or where it is delivered.
If the price is going up due to reduced volume due to e-mail, then raise the price across the board, don't blame Hawaii or Guam, just accept the price rises.
Parcel shipping is another matter...I got a 120lb item delivered by Aust post for $51.50...versus $70 to get 5lb sent to the US...those things should be priced on an as needs and where basis.
At least with the Post, if I'm not here to recieve, I can get it at the office after 16:30. A Courier or other service, I miss the delivery, and it's three days worth of phone calls to find a "mutually convenient" place and time...in 3 days, or the next town.
As I said, my experience is completely irrelevant to this thread, but also, my postal service made a profit last year while still paying a lot of people becoming redundant to leave the system...and I can have a passport interview (a a fee), buy WII games, stuffed toys, street directories, Printer cartridges, memory sticks, uncirculated coins gift packs etc.