It would be nice that some tags could be nested where's appropriate.
For example, tags inner clsases should be able to be declared inside tags for
their enclosing classes.

Practical example for

class Foo {
  ...
  class Inner {}; 
};

Currently:

<value-type name="Foo"/>
<value-type name="Foo::Inner"/>

This would be more pleasant:

<value-type name="Foo">
  <value-type name="Inner"/>
</value-type>


"enum-type" tags would benefit similarly from this improvement.

enum GlobalEnum {...};
class Foo {
  enum ClassEnum {...};
};

Currently:

<enum-type name="GlobalEnum"/>
<enum-type name="Foo::ClassEnum"/>
<value-type name="Foo"/>

Better:

<enum-type name="GlobalEnum"/>
<value-type name="Foo">
  <enum-type name="ClassEnum"/>
</value-type>