I believe it is in Israel's interests to win this war as soon as possible. This could be tricky as Hamas have embedded themselves into Gaza. They can easily mix into the civilian populations.

There is also considerable international pressure regarding protecting civilian lives. It seems like Israel have made considerable effort to protect civilian lives but this again delays operations. More delays will lead to more civilian deaths regardless of how cautious Israel is. The UN would know this but their actions often do not align with their mandate.