If you are following this topic, I recommend you read Tom Friedman first. Then one of the many excellent comments, one of which is here:
NYT trusted commenter Clawson, MI
“Not enough attention is being paid to the regional implications”
Friedman skips around the biggest regional implication. He mentions the Saudis, but he does not mention Israel.
Israel has become a problem to the US, even more so than the Saudis. It is become such a problem deliberately, as a policy choice to defy the US and defeat US priorities.
A better relationship with Iran is a good alternative to both of those troubled relationships. At the very least, it will shape them up by putting them on notice we have other options to shape the world to our priorities.
That potential impact on regional relationships motivates the hysteria about the terms of a deal that is otherwise pretty much what anyone would expect. They just don’t want any deal at all, not because of the bomb, but because it is a deal with Iran. That is exactly the most important reason for the US to do a deal with Iran.