The conformance clause must be more affirmative and avoid vague wording:
"In general, specialization-aware processors will be able to reliably process all conforming DITA documents,..."
avoid the use of "should" in conformance clause:
"Such processors SHOULD implement filtering."
It is OK in the normative body of the specification, but the conformance clause is supposed to remove any ambiguity, as much as possible. "processors SHOULD implement filtering" has its place in the body of the specification, but if it matters to conformance, the clause either can override Should as a Must, or the feature has to be a conformance option that must be part of the claim (see commentt #1286)