I'm sure it won't break Zawahiri's heart, if the rumor of AMZ's death is true.
All joking aside, we've wiped out so many of Zarqawi's #2 men, that there is a serious lack of experienced senior leaders. Zarqawi and a tiny handful of others are all that remain, and none from the old days. If AMZ is taken out, then the psychological blow to AQIZ would be devestating. He's really all that's holding that organization together. The individual cells won't be imparied on an operational level, and will continue to conduct attacks, but the overall organization won't recover from the setback before the elections.
Once public Iraqi perceptions change, then the insurgency is doomed. Of all the times for AMZ to buy the farm, now would be about the worst.