I will suppose that first of all beautiful XML would have to qualify as being sane
http://www.flightlab.com/~joe/sgml/sanity.txt
verbosity in XML is not considered a problem, but verbosity is relative. XML is itself more verbose than some other data serialization formats, but when an XML dialect is more verbose than the average XML dialects it is perhaps indicative of ugliness. An example of what I'm thinking of - XSL-FO seems more verbose than is necessary - I suppose other people can think of their own examples.
finally - how does it look in an indenting editor? I have a feeling that the beautiful formats when looked at in the editor will have a reasonable proportion of the major XML node types. That is to say it will achieve a sort of Platonic XML look, there will be a reasonable balance of element nodes, attribute nodes, text nodes - the format will not be too nested, but it will also definitely not be flat. There will be some elements without attributes, and no elements with a very large number of attributes - I say 8. Names are reasonable, there may be camelCasing but I dislike too many words portmanteaued together into a camelCased mess - no singlePersonResidenceIdenitifier. Names should not be long, especially not attribute names.
