I found "Dominion" to be an interesting, yet mixed bag.

The story starts out rather slow over the first couple of pages and is filled with a bit of cheesy dialogue and interactions between the characters. Combined with the sketchy, oldschool artstyle, I was afraid that this would be a rather generic, outdated police vs. gangsters tale.
However, the manga gains a surprising amount of depth as soon as the main plot sets in and Shirow actually does a really good job in developing the major themes (environmental crisis, human survival) and the characters to a satisfying extent within a relatively short time. Given that the manga is only 6 chapters in total, that seemed like quite an achievement.

So, is it worth reading? As an isolated piece of art, I'd say you can take it or leave it. However, "Dominion" is worth reading, because of the potential of its themes and its nostalgic value, given that the manga clearly shows story and character elements that would later re-emerge in Shirow's masterpiece "Ghost in the Shell". So, in a sense, reading "Dominion" felt a bit like reading a very early, still rather comical sketch for GITS.