I dont think we need to go down the where there is smoke there is fire route. These implementations are bad for a variety of reasons but not because XML is bad itself.

As I said, XML on Java is often a hassle but that is neither XML's fault nor Java's but the responsibility of those developers who thought going bananas on interfaces, factories, and alike is actually a good idea.

As for XML, its syntax is somewhat more verbose than JSON's but thats about it.

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Just to provide one very basic example

XML

  <people>
    <person>
      <name>John Doe</name>
      <dob>2000-01-01</dob>
    </person>
    <person>
      <name>Peter Smith</name>
      <dob>2001-01-01</dob>
    </person>
  </people>

JSON

  [
    {
      "name": "John Doe",
      "dob": "2000-01-01"
    },
    {
      "name": "Peter Smith",
      "dob": "2001-01-01"
    }
  ]

Apart from XML being more verbose (but also providing more context), these two documents are virtually identical, they even have the same number of lines.

And if one used XML actually idiomatically the example would slim down by a lot

  <people>
    <person name="John Doe" dob="2000-01-01" />
    <person name="Peter Smith" dob="2001-01-01" />
  </people>