Critical writing is what non-technical people think passes for analysis.
What you need is systems thinking, which analyzes all factors logically.
So-called critical thinking is a small subset of systems thinking.
So, quickly, my credentials:
When I was in high school (admittedly quite a few years ago), I took both AP English courses, passed with 5s, and wrote many persuasive essays with excellent teachers who frequently had extremely high passing rates.
As a high school student and for a few years after, I tutored students for the SAT, including the essay section, ...
If this is an undergraduate course, your instructor has the right idea. I think you're focused a little too much on the ordering part to hear the full idea of what a good thesis statement is.
Nothing is communicated with "Enkidu and Grendel have similarities." Any two of anything will contain at least some similarities.
I'm not familiar enough with ...