Saddam didn't have nukes "ready to fly" when Israel went after him in 1981. What he did have was a nuclear reactor that was "past the point of no return" or, to use abortion terminology "viable". It's not merely a matter of having a warhead and an ICBM or Bear Bomber armed and ready to go. It's a matter of having the infrastructure in place necessary to achieve a nuclear capability. The Iranians are still in the 1st trimester, but viability is rapidly approaching.
The Iraqi's were on the verge of getting to the point where they no longer needed any outside assistance and where it was mere time and inclination that would determine whether they had the bomb.
That's Israel's threshold. Right now, the Iranians don't have an independent capacity. They still need help from the Russians and the Chinese and various other countries. They're not yet at the stage where they have all the materials they need(ie like North Korea).
Israel WILL strike before Iran reaches that stage, unless the Int'l Community does it first.
However, when they do it will still be a limited op designed soley to eliminate Iran's nuclear capability, rather than an op to eliminate Iran(as an Iranian op against Israel would be). That is the "playing field" being reffered to. The goal of the op. For Israel, it's the elimination of the nuclear capability. For Iran, it's the elimination of Israel. If Israel were to level the playing field, as suggested, their goal would then be the elimination of Iran, not just their nuclear capability.
We are saying esentially the same thing about Israel/Iran. Israel will take action to prevent Iran from having the capability to launch nukes. It is estimated Israel has over 100 nukes ready to go. Israel has no interest, IMO, to annhililate the Iranian people, only the radical government/theocracy.