Thank you for the opportunity to help you with your question!
I feel that Gilgamesh is an epic because the poet remains objective. In other words, the writer or speaker does not take a stand on the issue. It's an important characteristic to the story because as a reader, we get to draw our own conclusions. Also, there are times when we get to see every side of the story.
It helps me to understand the epic because I believe what the speaker is saying. I don't feel that the speaker is biased.
Please let me know if you need any clarification. I'm always happy to answer your questions.