I tend to really enjoy Williamson as a writer but ultimately this felt like a real wasted opportunity. End of the day, what's really changed is:
1. The multiverse is now back to being infinite
2. The Justice League is in a limbo period where they're rethinking their purpose and what it means going forward
3. Nightwing is a beacon of hope and lightness that can lead the DCU forward
4. Deathstroke is out of commission
5. Amanda Waller is scheming with a new secret organization
Aside from the new status of the multiverse (potentially even more convoluted/confusing with the continued existence of Hypertime/the Dark Multiverse/whatever, just on a grander scale), most of this could have been accomplished with a story on a much smaller, more intimate scale, without going full cosmic nonsense and trying to tie it all back to the original Crisis and other things: something "kills" the League; Nightwing steps up and shows he's closer to Superman in terms of being an inspiring figure than Batman; Deathstroke tries to take advantage of the situation and gets slapped down; the League returns and takes a break to reassess what the League means going forward; and Amanda Waller looks at what happens and schemes and overreaches with a secret cabal, i.e. acts just like Amanda Waller. You can accomplish all of that without a crisis of infinite filler.
Is it the worst event? Of course not. But is it even close to being a good event? Oh god no.