David P. Goldman, who under the pen name Spengler
writes about foreign policy for Hong Kong's
Asia Times, has looked at all the variables and reached the conclusion that Israel should attack Iran. He concludes:
The strategic framework in which a unilateral Israel strike on Tehran makes sense is one in which all depends on Israel's capacity to improvise and dominate the situation through a combination of force and unpredictability.
You may not agree with his analysis but I think you will find his reasoning interesting.