Wowee! That's a bombshell! Revamping an entire universe? Only at DC...
It will be interesting to see how this occurs, and where it's all headed. I myself have always been a fan of constantly evolving storytelling, but a big slap in the face of DC continuity might be welcome. It is definitely a bold move and something no one would have expected.
It's a little frustrating, since there are some titles that are really clicking right now. The Bat books in particular are pulling me back into the DCU proper. What about Zatanna and JSA All-Stars? Wonder Woman would be an example of a title that could use this type of drastic measure. The editors say they're going to leave the successful creative teams alone, but that seems a little subjective in a lot of cases.
For now, my only prediction will be a gradual return to legacy numbering (ala Wonder Woman #600) for all titles.