Absolutely nothing is meant against it in that statement. It's fantasy Hamlet in a wonderfully inventive setting, with a parallel narrative that follows the development of a god. (That's where I was getting a hint of the Iliad; the power struggles and battles of the gods that run alongside the course of human events.) And it's not beat for beat Hamlet, but it has more beats in common than, say, The Lion King. And I've been known to accuse The Lion King 1 1/2 of being Rosencrantz and Guildenstern are Dead in spite of never having seen the former. Let's be realistic here: most of Shakespeare's plays were based on pre-existing stories. The point is how well the author/playwright does it.
And how well does Leckie do it? Well, I'll admit to having some trouble getting into it. Full disclosure: I have trouble with second person. A lot of it. The Hamlet narrative is told in second person, narrated by the god who narrates the god narrative in the first person. I know that some people find the second person very immediate, but for me, it's an obstruction to getting to know the POV character. First person puts you in the POV character's head, and third person, especially close third person, tends to tell you a lot about the POV character, but second person... well, people don't generally describe the person they are addressing to themselves.
I was on the verge of putting this book down around twelve pages in when it turned out somebody was out of the picture and his brother had taken his place instead of his son and heir and I went "Oh, it's Hamlet. I think that the 'you' being addressed must be the Horatio figure." And then I had a handle on it. I could sit back and relax and appreciate the literary quality of Leckie's writing, and occasionally go "yeah, that was Polonius" or whatever.
All in all, a difficult book to get started on, but one that makes persevering worthwhile.
Overall: A-