Allowing choosing user name on account creation

I singed in with Gmail the provider. My name on gmail is Allan Daemon, and instead of taking the complete name, or asking-me my username, it just picked Allan4, and I found it terrible.

So, allowing user been able to change the user name, whether in the profile settings page, whether when the user creates a account, is something very desirable.

One alternative is at least try to stay with something close with the original username. I have a unique user name all over the web (Allan Daemon or AllanDaemon) and here on speakerfight is the only exception.