But a plainer style, not seeking to arouse the emotions, should be used if a tighter argument is desired. R can be treated as an art. Cicero treats the matter of R rather than its ends, which are outside its scope. See also my reading notes when I write them. Crassus is the one to discuss style in all its seriousness.
Diction is urbane and only thought about when a mistake is made.
Language is to be suited to the audience. The complete orator needs to know law, customs, religion, and many common examples. The classical period split R into invention, structure, memory, style, and delivery. Therefore invention, structure, and memory are the province of logic, while style and delivery are reserved to rhetoric. So this version of R focuses on tropes and schemes, and it leans toward the ornate.