The term "most diagramed" can be substituted with various synonyms depending on the context of its usage. For instance, if referring to a process that has been illustrated graphically multiple times, "most illustrated" or "most represented" could be used. Alternatively, if describing a particular subject that has been analyzed and broken down into details repeatedly, "most deconstructed" could be a potential synonym. Another synonym could be "most mapped out" which implies a thoroughness of exploration and organization. Ultimately, the choice of synonym will depend on the intended meaning and emphasis of the sentence in which it is used.