DCAT-AP includes a single property to refer to an Agent (person or organisation) related with a dataset: publisher. While in some national profiles, additional Agent roles are defined (e.g. creator, rights holder).
The discussion on the issue is available here.
The DCAT-AP specification version v1.1 has one section related to agent roles. The specification is available on this link: https://joinup.ec.europa.eu/rdf_entity/http_e_f_fdata_ceuropa_ceu_fw21_f5be94659_b942a_b4d1d_b9868_b644621558cb5.
Throughout the interviews with DCAT-AP implementers, no widespread use of other common types of Agent roles was found.
Considering the current use made of different types of Agent roles, no extension of the number of Agent-related properties in DCAT-AP is currently foreseen.
Depending on the emerging needs, an extension could be considered in the future.