Remember the first reboot of the DCU was planned for close to two years-and even then there were glitches and unexplained gaps-who replaced WW in the Justice League, were their analogues of Superman and Superboy in the 30th century Legion, what were Power Girl's and Wonder Girl's "real" origins, etc.
This was barely planned out in advance AT ALL-Warner Brothers finally noticed DC hadn't bested Marvel for over eleven years-not even for a month out of a decade. In no uncertain terms, editors and staff writers were told the situation had to change, and radical action was in order to do so. The Flashpoint mini was rewritten midstream to turn it into the "event" that rewrote the DCU.
This seems to have worked for DC in the short term, making them very competitve with the competition, which is also good for the industry as a whole. Long term I am very doubtful. You can't reboot every 3-5 years, and Before Watchman can only be down once (though if they continue to sell well, we WILL see an After Watchman or World of Watchman event.).
All my best.
The Contingent: When all other super teams fail...