Hamas is a blessing to Israel. If not for the external threat, Israeli society would roll still faster to the left, decomposing in the process. If Arabs are no longer the enemy, the bourgeoning Muslim population of Israel is not a threat. If the Palestinian state is formed, the Jewish state loses Judea and Samaria.
If Hamas becomes weak to the point of acknowledging Israel, Hamas will no longer represent the Palestinians, and their society will be torn between various factions, creating a tumultuous state at Israel’s borders. Palestinians lack a work ethic and the culture of education and will remain perpetually poor - the ideal breeding ground for terrorists. Hamas employs Palestinian radicals; if Hamas ceases to be anti-Israeli, the radicals will dissolve into many groups, and the Israeli security apparatus won’t be able to reign in such a multitude.
One good thing about non-belligerent Hamas and the Palestinian state in general is that the Israeli government would lose its excuse for totalitarianism, mismanagement, skyrocketing taxation, and the general license to destroy the Jewish state in the name of national security. After Palestine settles down, Israel could free the resources to rise up. That is unrealistic.

