I too would like to see the FormBase classes brought back. There's a lot of standard generated code in my forms that I very rarely alter, and would prefer to be able to regenerate at will without breaking my form customizations.
Mind you, you can accomplish this now yourself by altering the templates the following way:
1) Change the filename/class name/location in templates/db_orm/drafts/_qform_edit.tpl.php to add “Base”
2) Rename the file _qform_edit_base.tpl.php
3) Create a new _qform_edit.tpl.php template file with just the basics (the class definition stuff in the old file, but extending *EditFormBase instead of QForm)
4) Do the same for the list pages