Sure looks to me like it could be called a "workstation" Look at what Sweetwater has labeled "workstations".
I was not disputing that there are workstations, just that workstation and synthesizer are not mutually exclusive terms. If it can synthesize it is a synthesizer. And perhaps if you can "work" with it it is a "workstation". Semantics, semantics, semantics. To know what it is you have to look further than just a name.