Some editing tools don't show attributes while you're editing the file, instead you have to use dialog boxes for editing the attributes and that can make a attribute heavy XML very tedious to edit. The attribute - element question is for the most part a cosmetic issue. Therefore I think that if letting go of attributes makes the XML file much easier to edit then you should avoid attributes, but if you are concerned about the readability of the file attributes should not be avoided. Attributes have datatypes. Attributes take less space since they have no start and end tag.
Values containing quotes can be a bother.
Attributes can't contain other elements. White spaces can't be ignored in attributes. Attribute values are harder to search for in search engines. Attribute values often don't appear on the screen in editing tools. Attributes can be slightly more awkward to access in processing API's.