I acknowledge Gilgamesh's transformation wasn't an overnight occurrence, and therefore, these two periods of time of these two very different characteristics [of Gilgamesh] are on the opposite ends of the "plot timeline". Why would anyone read a book that didn't have the many other medial elements of Freytag's Pyramid. The same goes for riding a roller coaster while unconscious, only waking at the end. Or eating a sandwich with out fillings, two slices of bland bread. The same goes with reading a good story.
Linguistically, The Epic of Gilgamesh (translated by Andrew George) has simple vocabulary but complex wording. Other ancient Greek texts I've read tend to be the opposite (simple wording; complex vocabulary). Therefore, a dictionary is not readily needed in this text, but one could be helpful.