NATO doesn’t really have the authority to veto a member country’s policies for their own defense. What it would bring to the table is an ability for Israel to invoke Article 5 and demand assistance from other NATO countries in the event of an attack. Under this article an attack on one member country is considered an attack on every member country.
I also think you’re right that allowing Iran and Saudi Arabia to have nukes would validate the claims of other nations, including Egypt, Turkey and Syria, to have nuclear weapons.
Does anyone really think that Europe or Turkey would come actively to Israel's defense when attacked? I don't think it's worth the paper. Look at the contribution the Europeans (with one or two exceptions) make in Afghanistan... insignificant posturing.
“What it would bring to the table is an ability for Israel to invoke Article 5 and demand assistance from other NATO countries in the event of an attack. Under this article an attack on one member country is considered an attack on every member country.”
See, this is what I was thinking also, in my first post by saying that Israel should be included in NATO. They just really need more support closer to their borders, besides the United States.