Many in Israel are still scarred from the last time Israel sent ground trips into Lebanon (1982), just like the US for many years was scarred by Vietnam. This means that Israel is very reluctant to commit ground troops. Therefore, the reliance on air power.
The problem with what you are suggesting is that the international community has consistently dissapointed Israel. In 1967 U Thant pulled out the UN troops in the Sinai paving the way to the 6 day war, a few years ago, UN troops in Lebanon stood by and watched as Hezbollah kidnapped 3 Israeli soldiers. Relying on anyone else to guarantee Israel's security is a very dangerous and losing proposition.