You present a persuasive argument for the abandonment of the 5-paragraph essay and suggest a new format for presenting an argument... However, you did not provide much information on what is expected to go in between your introduction and conclusion? You suggested this format opens the essay to compare/contrast, cause/effect, analysis, etc... but how do you suggest students structure an essay with these approaches in practice? Any piece of writing needs some structure and main ideas that are then supported with various pieces of evidence (whether you are writing a historical thesis or a persuasive essay)... If you are abandoning a "main idea followed by supporting evidence" format, what do you propose should take its place? Or perhaps my understanding of the 5-paragraph essay you are speaking of is incorrect?
Whenever possible, use strong subjects and active constructions, rather than weak verbal nouns or abstractions and weak passive or linking verbs: instead of "Petruchio's denial of Kate of her basic necessities would seem cruel and harsh...," try "By denying Kate the basic necessities of life, Petruchio appears cruel and harsh--but he says that he is just putting on an act." Don't forget that words and even phrases can serve as strong sentence subjects: "Petruchio's 'I'll buckler thee against a million' injects an unexpectedly chivalric note, especially since it follows hard on the heels of his seemingly un-gentlemanly behavior." And remember--use regular quotation marks unless you're quoting material that contains a quotation itself.