There is no single "classical" model of rhetoric. The "classical" period lasted almost a thousand years and included writers as diverse as the Older Sophists, Plato, Aristotle, Quintilian, Longinus, and Augustine. Some classical authors believed in the importance of systematic logical analysis, while others were primarily concerned with the effect of style. Christian writers emphasized the importance of divine grace in persuasion, while others were concerned with using emotions to trick audiences. Some writers saw rhetoric as opposed to education and as a form of immoral trickery, while for others, good rhetoric depended on the good moral character of the orator. Different classical systems have different strengths and weaknesses.

Toulmin is best known for a rigid six-part system consisting of a claim, warrant, and other elements. This can work well for specific types of argument, but not all issues are suited for this formula. Toulmin himself was interested in informal logic, and his method may not always take into account factors such as how best to affect the emotions of the audience.

Rogerian argument is based in the effort to find common ground among positions. While this may work well when there is common ground to be found, it relies on the assumption that such common ground exists, which is not always the case.