Bringing back Barry Allen? I thought it was a bad idea but the writing on the current FLASH series has made me change my mind. When written well he really is more interesting than Wally. (Not that I don't like Wally.)

ZERO HOUR -- pointless series. Didn't change anything memorable except to "negate" Captain Marvel stories that hardly anyone read anyway. Yes, it gave us a Legion reboot. And then we got another one in 2004...

INFINITE CRISIS -- I liked it more than I should have. Still do. It's better than COIE, I'll say that! And I liked the SECRET SIX lead-in series because, well, Gail Simone. 

I wouldn't recommend it to anyone who hasn't read it, though. And in any case, Geoff Johns killed Ted Kord, but whatayaknow, Ted Kord's alive again as of 2016. 

FLASHPOINT -- I think it's a pretty great story but I hated how it was used to introduce the New 52. Johns originally planned on the ending make everything go back to normal but he was outvoted and, hence, the reboot. (BTW, I've read enough of Johns' run on the rebooted JUSTICE LEAGUE title to be able to tell that his heart wasn't in it. He liked the DCU as it was.) 

Everything in the Crisis got redone after Pu52 and the Watchmenboot. But most of the Crisis' effects were undone anyhow, between Infinite Crisis and Final Crisis.

The Crisis on Infinite Earths was based on a lie anyhow that DC KNEW about... that NOT every title and character would be restarted from scratch. And I feel that to do that, they would have needed a "super editor" to watchdog every... single... title... to make sure that it all coordinated properly. Mr. Byrne established when Batman and Superman first met... so there couldn't be a Justice League story implying that the two met during the first JLA adventure.

It wasn't possible just because their best seller at the time, the New Teen Titans, was IMPOSSIBLE if the COIE had worked as planned. Robin? Wonder Girl? Beast Boy? Kid Flash? None exist right after the Crisis. How to start Batman from square one, with the first page showing the Waynes ALIVE, and restart the Titans with just Cyborg, Raven, and Starfire?

Pre-Crisis, there were illogical elements and confusing issues... but they were so minor - SO insignificant - that they could just be ignored, unless a writer was desperate... or a super geeky ex-fanboy who had no business writing comics. Such as Marv Wolfman and the Powers That Be who inflicted Crisis on us in the first place. Post Crisis destroyed any sense of logic or continuity in the DC Universe... which, I suppose, might be what they wanted all along...

*It was SUPERBOY AND THE LEGION until #259.

Dave P: "Worlds will live, worlds will die..." Well, that happened back in Action Comics #1, so it wasn't exactly a new concept. :)

"....and the DC Universe will never be the same!" Boy, THAT was true! It became self-contradictory, confused, illogical, and even lost. But while that was the result, and was implied, you're right that nothing was printed in the comics about it. Why would it? Marvel was beating DC at the time anyhow... why drive away more readers?

I found it strange and yet was glad that Shooter and DC hedged their bets with the Death of Ferro Lad by establishing a twin brother with the same powers and then DIDN'T use him to replace the first one. 

I have no use or affection for all of the desperately scrambling Final Night era Ferro Lad material in which he was shown as shy and unsure of himself with a twin brother who is killed in a prison uprising. Nothing was gained and everything lost from the original story.

Of course, Ferro Lad had already been resurrected ala' the SW-6 batch of LSH temporal clones introduced into the Post-Crisis proceedings to restore some sense of the book's previous innocence during the dour, glum, & violent Five Year Gap stories. Tediously fannish in the extreme.