Some of the more interesting answers from an interview CBR did with Bob Harras and Eddie Barganza:
Berganza: Just because we're starting with new #1s doesn't mean we're getting rid of the history attached. A lot of those big, important storylines are remaining in tact. What happened in "A Death In The Family" stays true, and so does "Blackest Night," "Brightest Day," "The Killing Joke"...
Harras: "Identity Crisis." Again, this is a well thought out process before we went forward.
Berganza: The thing you have when you're working with Geoff and Jim is that they're giving you some background as to what brought these heroes together. Grant is introducing Superman into the world in a realistic manner to ask "What would you do with this guy who has these powers and abilities?" It gives you that perspective that we lose sometimes because we're in comics on a day-to-day basis. It has that realism and that initial wave of real reaction from the public. And that idea builds out to the other titles and the guys are working on.
Harras: We've taken a long time to build up this relaunch, and one thing is that we did look at how all the continuity of our characters worked and the events that were very important to them which would ripple across their loves. Eddie and his team created a timeline of the DCU and the DC characters that is very important to us. It's a document we're using all the time going forward for all the characters that incorporates their pasts and serves a platform for future stories.
Berganza: It's a living, breathing document, and as ideas come through, we find out what fits and what makes for the best story. We keep adding to their lives.
Harras: But everything's based on what's most important to the character and what events have had an impact on their lives that will drive story in the future.
Berganza: And what's nice is that those events are usually the ones that fans really like and the ones that we like. It makes for a nice history.