1. span, dir, emph contain PCDATA, not other inlines

2 "The elements may also have an xml:dir attribute for tagging the written language of the contents of the element": should be xml:lang not xml:dir

3. Might be useful to allow test to be a child element rather than an attribute, since newlines
in attribute values tend to disappear because of attribute value normalization.

4. abstract="true" seems redundant

5. Unclear which nodes patterns are applied to: certainly element
   nodes; root node too; what about attribute nodes?

6. count(sch:*) = count(sch:assert |sch:report|sch:key|sch:extends ) doesn't work very well
   since it doesn't pinpoint location of element that should be there

7. Why do name and value-of use different names for their attributes that specify a path?

8. In the DTD ns attribute on schema should have type uri not fpi.

9. ns attribute is problematic. How does it interact with namespace declarations?
Impossible to implement in XSLT without relying on non-portabl features.

10. Why does DTD have rule* in content model for pattern, whereas S4S requires
at least one rule?

11. S4S doesn't disallow unknow, unqualified attributes on schematron elements.

12. S4S requires at least non-whitespace character even on namespace qualified attributes
on SChematron elements.

14. S4S doesn't check that empty elements don't contain text

15 DTD is inconsistent in type for xml:lang (p and report)

16 type of match should be path

17 name of ns attribute on schema is bad: doesn't reflect meaning that applies to roles

18. position() and last()

19. Whitespace handling in messages underspecified.

20. icon attribute on key doesn't make sense to me

21. keys in abstract rules

22. diagnostics wrapper element seems unnecessary
