The main reason why hamas is not launching is because olmert is no longer in power.Even after cast lead, they still fired rockets in large numbers compared to now. They knew he was afraid of war and so continued. Not so with yaalon, bibi and peled. Notice that barak's presence did not deter hamas.
Once olmert left, hamas rethought their interests and decided not to play with fire. And bibi responds to every attack, while olmert responded to the 20th attack with puny retaliation because he was afraid.
Now to get a better fix on just how bad olmert was, look at his interview with bbc. As klein halevi says, Olmert was arrogant, and boasted with smerk on his face and boasted some more...things like israel is a very powerful country. He was an obnoxious interview and israelis were frankly stupid to vote for him. He is a total fraudster.
Lastly, cast lead helped and israel bent over backwards compared to normal army conduct. israel may want to do its own investigation, and then if the results as expected confirm the idf so far that goldstone's charges are baseless, then sue him for defamation in civil court in England where he resides. He slandered the state of israel in a report that did not rise to a legal standard to make his conclusions, damaging ones. he should be sued and israeli attorneys should be thinking about it.