It is inappropriate for 2 reasons:

• Not all the items in the first fieldset (with legend "Required") are required - there are plenty of optional and advanced fields!
• The fieldset legend is spoken by screen readers like JAWS before each field in forms mode, for example "Required Username Graphic Required field Edit admin ..." - this is too many "required"s!

The attached patch uses the string "General", which I think is better.
This blocks bug MDL-11293.

Thanks, Nick