Dear Xhamster,
There are many reasons behind changing username of any users. First of all almost all the sites are giving opportunity to their users to change their username at least three times or more. But as my personal opinion it's best and smoother site for all visitors but this lagging feature hunting like nightmare. Many users are looking forward to have this feature and to change their username at least minimum 2 times. Hope this feature will be added soon. Thank you.