The definition in Commons Annotation Vocabulary is not a mere copy of what's in DCT with the documented addition of making it a owl:AnnotationProperty, but adds the triple :
<rdfs:subPropertyOf rdf:resource="&skos;note"/>
That may or may not be a good idea but it adds a dependency and it's a significant change that should be flagged.
In fact, given that SKOS itself makes use of DCT, that makes for a somewhat undesirable circular dependency though not formally stated.

If an aim is some sort of unification then maybe skos:definition should be made a subProperty of dct:description.

Little best practice or guidance is given in either the spec or the ontology. By the fact that they're included it seems that skos:prefLabel and skos:altLabel are recommended. However they're not actually used in this or any of the other Commons ontologies.
Commons itself provides an alternative with its Designations ontology. And OMG provides a strong capability in MVF.

Users of Commons should be warned about the anti-pattern use of rdfs:label as the primary in conjunction with skos:altLabel which makes it impossible, with reasoning enabled, to return only the primary (since skos:altLabel; is a subProperty of rdfs:label)

The definitions taken from SKOS seem altered and incomplete.
For example here is the official definition from SKOS RDF file for altLabel. The Commons version changes the label (using "tag" instead of "label") and omits the comments, one of which is the important (informal) disjointness constraint, and example.

<rdf:Description rdf:about="#altLabel">
<rdfs:label xml:lang="en">alternative label</rdfs:label>
<rdfs:isDefinedBy rdf:resource="http://www.w3.org/2004/02/skos/core"/>
<skos:definition xml:lang="en">An alternative lexical label for a resource.</skos:definition>
<skos:example xml:lang="en">Acronyms, abbreviations, spelling variants, and irregular plural/singular forms may be included among the alternative labels for a concept. Mis-spelled terms are normally included as hidden labels (see skos:hiddenLabel).</skos:example>
<!-- S10 -->
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#AnnotationProperty"/>
<!-- S11 -->
<rdfs:subPropertyOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#label"/>
<!-- S12 (not formally stated) -->
<rdfs:comment xml:lang="en">The range of skos:altLabel is the class of RDF plain literals.</rdfs:comment>
<!-- S13 (not formally stated) -->
<rdfs:comment xml:lang="en">skos:prefLabel, skos:altLabel and skos:hiddenLabel are pairwise disjoint properties.</rdfs:comment>
<!-- For non-OWL aware applications -->
<rdf:type rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property"/>
</rdf:Description>

SBRM and other OMG processes need to be able to connect documents to the components therein. RTF members have requested that we add these terms to the documents ontology to facilitate mapping to other document ontologies as well as for extension purposes.

Several OMG members have requested a general ontology that includes sites and facilities, which are currently modeled in FIBO, primarily for lending and asset management purposes, but they are also needed for retail and manufacturing. The relationship between a site and a facility is many to many, and modeling them for manufacturing as well as retail, energy, military, and other domain areas can be tricky. Having the general pattern that can be extended by any domain area would be very useful for extension purposes.

There is a gap in the quantities and units ontology whereby we cannot represent counts of things, which do not necessarily have units, nor can we properly represent ratio values, which may involve scalar quantity values that do not have units. There is also a challenge in representing ratio values more generally, since there is no numeric value representing the ratio on the class.

There is a gap in the quantities and units ontology whereby we cannot represent counts of things, which do not necessarily have units, nor can we properly represent ratio values, which may involve scalar quantity values that do not have units. There is also a challenge in representing ratio values more generally, since there is no numeric value representing the ratio on the class.

1. County and FederalCapitalArea should be subclasses of CountrySubdivision

2. FederalState should have synonyms rather than this in the note "variously referred to as a state, province or canton".

3. Several annotations on geographic region identifier and a few other concepts need clarification

Rather than classifying 'something' an aspect should classify a set or group of things - at a higher metalevel than 'quality' in BFO, for example. This impacts the Classifiers ontology, in which Aspect is defined.