There seems to be various views among botanists. The Catalogue of Life is a community-based approach and states this species is a synonym of R. caesia. The board of COL includes scientists from Netherlöands, Belgium, France, China, University of Illinois. On the other hand, there is World Flora Online, and its predecessor The Plant List.org, which is supported by the Missouri, New York and Edinburgh Botanical Gardens, as well as Kew, which state this species is an ambiguous or unresolved taxon. As a non-botanist, I would wait until all agree before merging the listings. However, we can add your comments as a worthwhile note showing botanists' confusion.
In my opinion, there should be some publication explaining why two species are considered synonyms, thus superseding earlier publications. For this reason, I have e.g. refrained from adding the many new names placed forward in the publication "Die Wildrosen (Gattung Rosa L.) im Europa-Rosarium Sangerhausen, nach ihrer Verwandschaft geordnet" (2007) by Brumme & Gladis, as there is no evidence of research behind their listings.