Having to log out and back in, especially with a secure password, is a tedious procedure when all you want to do is move from one character to another.
Don't know how easy this would be to implement as I don't know how data is passed between the connection/login/account/'instance' servers when a player logs in/out.
What I do know is, it would make my life much easier!
Also, another annoying feature I've found with STO is that it shows you as 'Online' to friends when you're at the character select screen.
Problem is, they can send you tells, which you cannot reply to because there is no chat interface in character select, and the tells are not displayed when you finally log into a character. Meaning you have to hit backspace to reply, and then ask the sender to resend their original message.