If roles are (in part) given by the construction itself, we are not committed to a small set of roles
Roles which are 'abstract' (i.e. which appear on lists devised by linguists) are those which are echoed across verbs and across constructions
Some arguments feel 'natural' and others feel 'added on' - the 'natural' ones are represented in the lemma, high frequency links between verbs and VAS constructions are lexically-stored while low frequency links are formed on the spur of the moment