Unfortunately, so far we haven't heard any indications on the Iranian side of what it is they would want in return for a deal.
We're in fact further behind with Iran than we are with North Korea. The North Koreans at least say that if we provide them with this, this, and this, then we can have a deal. The North Korean list seems to be ever-growing, and there are lots of problems in negotiations with them, but at least the North Koreans say that if we give them enough, and make things sufficiently attractive, we can do a deal.
With Iran, we haven't heard that. And that's very discouraging. It reflects the extraordinary confidence that Iranian leaders have had in recent years that their country's geostrategic situation is so good that they don't need to think about a compromise.
The pattern of negotiating with Iran on any issue, whether it's a business deal or a political deal, has been stalemate, stalemate, stalemate--until breakthrough. In many of the negotiations, what Iran ended up agreeing to was much less attractive for Iran than what they could have gotten at an earlier stage. So they are tough, but they are not particularly effective at negotiating.
Some in Iran have suggested that this is what's going on with this nuclear issue. Iran could get a lot out of a bargain with the international community about the nuclear program--now--but if they drag on the discussions for a long time, the world may decide that Iran is such a difficult partner country, we're prepared to offer them less.