Looks like you already read it, but I'll say this: I liked it when it came out, but ultimately whatever impact is was supposed to have was moot.
The delays forced it to shoehorn in references to Sanctuary and the Dark Multiverse, which the story didn't have any impact on.
DC flat out ignored everything in it and used Death Metal to do what Doomsday Clock was intended to do. The first issue of Death Metal even flat out says that Doomsday Clock "did not have the desired effect."
Because of all the delays, other writers started using characters that Johns was saving for the end of Doomsday Clock. Snyder yanked the JSA for Death Metal, and Bendis rebooted the Legion of Super-Heroes before it was done and brought Clark's parents back. Young Justice probably should have been held off until after it was done because the YJ4 were huge parts of the storylines leading up to it, but the book came back a whole year before Doomsday Clock was done (and severely suffered for it).
The book had to pivot to being a Superman love letter at the end and force in references to 5G, which was scrapped.
If the only comic you ever read was Watchmen and you picked this up, it might be ok. But following DC the whole time it was coming out, I can't help but resent it because it forced the whole publishing into a holding pattern because it was delayed so much. Those two years were an absolute shyt show creatively for DC, and the book didn't even have the impact it had been built up to. I'd say the same thing about Three Jokers, since it was delayed even longer and the final product was
.
I don't know if any of that answered your question, but I felt like ranting about it.