A large operation in Gaza is no more attractive a prospect to Isreal than to Hamas and should be avoided if possible. If Hamas wants to control Gaza, they can also take responsibility for Gaza. If they want to, Hamas can use the same military force that they used to drive Fatah out of Gaza to curb the various militant groups that are launching rockets. It is preferable that they do that job than our soldiers do, and hopefully with as little internal bloodshed as possible. Effectively cutting off the militants' supplies would be one way. Let them do house to house searches for rockets if they have to, arrest militants, but let them enforce that cease fire themselves. If Israel gave them a deadline after which we must have total quiet, than things might move pretty fast. Knowing that any renewed rocket fire will bring down a large scale operation would also be a deterrent in the future. I doubt they want it any more than we do.
IDF reservist, 44, dies of heart attack during training (Haaretz)
from the article: Report: Hamas wants cease-fire with Israel in the Gaza Strip