I expect Israel to go into Gaza with quite a bit of strength in a long-term operation, and frankly I feel it's far due, as much as I detest war. The reason I think as such should be pretty obvious to those who have been keeping close touch with developments over in that region for years now, namely that Hamas and Hezbollah have armed themselves to the teeth (it's believed that Hamas alone has roughly 10,000 missiles), and they have made it abundantly clear that they are intent on destroying Israel.
What makes it more likely this time that Israel may not stop is that Hamas' missiles have gone further into Israel, reaching areas around Tel Aviv, Jerusalem, and Haifa. If we project maybe five or ten years from now, their missiles are likely to get bigger and more accurate.
As far as I'm concerned, you gotta do what you gotta do to protect your citizens. Would any other country do any different? It's too bad as it's innocent civilians that typically pay the highest price.