Because I'm both a dictionary nerd and a future-imagining nerd, I read this book from start to finish as a primary source to get a full sense of how they treated both. The politics expressed are not important and I would review it the same way. Sometimes what would be helpful observations elsewhere highly varies by author here, so I'll skip that.
Credit: After the copies of the Declaration of Independence, Universal Bill of Human rights, the Taguba report, and an uncharacteristically insipid essay by Vonnegut, etc., every author's name is attached to the entry they wrote. At the end of the dictionary there's an index linking each author to all their entries and then a short blurb for each of them and the artists. This is very much a collection of author ads.
Dictionary-ness: This is not very dictionary-y. It's more of an encyclopedia. The authors collected here are storytellers, not editors or definers, and the number of entries in this book that are in dictionary form is vastly overshadowed by sprawling, sequential series of text. Sometimes this is intentionally done as a subversive joke, but with the non-coordination of a three-month schedule, too many people made that joke for it to land. Sometimes authors did not care to split their ideas into many different terms, just glomming them into one big line. This is better fit for an encyclopedia. However, those who broke separate ideas into entries really shined. These entries functioned as a series of callbacks that build how such an idea really works. I do believe they intentionally relied on the order of the alphabet in order to pace exposition to what would be confusing to piece together, so it's not like that doesn't have its tricks as well.
I didn't discredit the long-form, though. There was really rich dirt for further digging, like turning the future into an optimistic fairy tale, turning Ancient Egyptian setting into political events that involve voting out the Pharaoh. There was even niche and offensive fetish porn with no observable other purpose. That soil was not very rich.
Idea repetition: far too much. Since these authors seemed to work in isolation from each other, I think this book would have benefited immensely from more base guidelines and a metadata creator/manager. Basic guidelines would be the date this dictionary "was" "published," and stuff like that. Contributors set things all over the coming millennium, up to 3002. The United States kept the same borders. Contributors beat W. Bush, the Iraq war, and other current events into the ground. Similar ideas—namely, the creation of a second USA in a pocket dimension—got recreated several times because there was no communication. If people could scroll the metadata and add to each other, this would be a much more interesting book.
Drawings: What's usually visual example in dictionaries is in here re-imagining of specific entries as political cartoons.
I'll end the overview here, I guess.