In order to determine whether it’s a good idea or not, we have to see whether it helps to achieve the goals of US and its allies.
The ultimate goal of the US and its allies is to simply topple the Iranian establishment in the way that Iran wouldn’t be able to come back at the international scene anytime soon. Many people say it’s also to restrain Iran from expanding its influence throughout the region and beyond.
Sanctions are not going to bring down the establishment simply because they are ineffective. They are ineffective because number of countries like China, Russia, Turkey and India are not going to abide by the set of rules that the US unilateral issued, also, because Iran is not the type of country that could be defeated by only sanctions what this means is that Iran is an independent state that can provide many of its essential needs like food and medicine. These type of sanctions will work on smaller countries that can be squeezed not Iran and definitely not Russia or China.
But why is that a bad Idea especially in the case of Iran? What the US feared the most about Iran is called Islamic Revolutionary Guard Corps or IRGC. IRGC was one of the main element that was responsible to pass through the 2012-2015 Obama sanctions by finding alternative ways. Now guess what, IRGC gets more experience and finds more connections globally when they’re ordered to find ways around sanctions, they become more powerful by having more responsibilities. So this is a classic example of unintended consequences or blowbacks in politics and international relation.
Soviet Union collapsed not because of economic hardship (although it had its effect) but when Soviet Union last leader Mikhail Gorbachev thought west was his friend and officially invited its enemy to his house. Pretending to be the friend of Iran is the most effective way to topple their establishment. So, the Iran deal was not achieved because Obama loved Iran but because he thought this strategy is more likely to work than others.