Agreed. It's hardest for less savvy users. Especially when they make a typo in their username or password and the password login fails. Then it unfolds like this:
- Make typo in login.
- System tells them it was an incorrect username or password, but it ALSO then switches from the default domain you assigned via GPE back to the local machine after a failed login.
- User does not notice this. So they re-enter their password, this time correctly, but since its now set for local so it fails access again because we dont set them for a local account.
- Then they call complaining that thye hate the new system.

You can explain to them about the typing of "domainname\" but why do thye have to type anything? Thats more work. Drop down choice much easier for them to understand and rememebr. They arent programmers who are used to typing command prefixes first.