FileVault is encryption. This way, if someone steals your computer, they can't get any of your data. FileVault is a good thing. Most people don't stare that login screen for too long. They just login and it goes away. Most people also stay logged in. There really isn't much need to log out.
However, due to the way the boot up process works, it is very difficult to change that initial sequence. If you were able to easily change any of that data, then, in theory, an "attacker" could also do that and change the operating system. Yes, I realize your computer is in a secure location and the chances of this happening are infinitesimally remote. Those facts don't matter.
If it were possible to change the FileVault boot data, there would be headlines on every major media web site and TV show about "MAJOR APPLE SECURITY FLAW" and then Apple would change it and you wouldn't be able to choose your login screen anymore. All Apple is doing is cutting out the middle-man of the bad press and jumping right to the end. This is the world we live in now. We can't have nice things.