If theres one thing the annoys me to no end its swapping characters. I have 5 characters(and I know some people would have more) bu evreytime I log on I have to go on each character and check mail and auctions, Which takes like 10 minutes.
I think that the auction house should be account based, So I can see and manage items and bids from different characters on my account. I also think mail should be the same way( so if somebody sends mail to character c and I am on character f I can check the mail) I would even go as far as putting a bank slot that is shared through out the account.
Another thing that really annoys me is having to log on character B to look at the LFM the log of him and go onto to character E to join that group. I think the LFM should be available on the characters selecting screen so I can exactly what groups are forming and pick the character that I want with that information.
I realize that completely redoing the way mail and the auction house is done is pretty big and redoing the character select screen is also quite large and that there are lots of other important things that you need to do but I really think this would make playing the game allot easier. I hate 10 percent of my time just changing characters!