Some Limitation or Disadvantage of XML

XML markup has a few disadvantages:

It can be verbose unless element and attribute names are chosen with care. In large documents the markup overhead need not be large, but in short messages it can be significantly more than the actual data, especially when the element or attribute names are concocted by machine. Overlapping markup is not permitted (an element cannot start inside one element and end inside another): element markup must nest hier
archically. Some of the software is truly mediocre.