I know we can modifiy the XData Class but here are a few addtional attributes may make default class a little more complete :
Last-Logoff
Last-Logon
Phone-Fax-Other
Phone-Home-Other
Phone-Home-Primary
Phone-Mobile-Other
Phone-Mobile-Primary
Phone-Office-Other
Social Attributes
ProfileUrl
LinkedInUrl
TwitterUrl
InstagramUrl
FacebookUrl