Against an implacable, well-entrenched, non-state enemy like the Hamas, Israel needs to “mow the grass” once in a while in order to degrade enemy capabilities
Israel didn’t effect a significant change in the security balance versus Hamas in the Gaza Strip. A draw with the Hamas is strategically unsatisfactory.
Israel's reluctance to inflict a decisive defeat of Hamas in Operation Pillar of Defense indicates its desire for a new arrangement for the Gaza Strip. A preferred outcome would be an Egyptian role in Gaza, providing Israel with a real government with whom it could negotiate.