When You Deal With the Devil, There Is No Good Deal
The deal is bad not only because it keeps the regime in power, but because it leaves in the regime's hands those 11 tons of unenriched uranium, which can still be enriched.

Reaching a good deal with Muslims is difficult, because in their view every agreement is merely an interim stage aimed at weakening the enemy, in keeping with the doctrine of Hudaybiyyah. For that reason, in the current context Trump's deal is not bad, but over the long term, it is very bad.
A good deal would have done the following:
Halted the ballistic-missile program, stripping Iran of the conventional umbrella beneath which it can revive its nuclear development.
Required Iran to surrender 11 tons of unenriched uranium.
Obligated Iran to compensate every country it harmed that had no part in the war.
Refrained from handing the regime $24 billion — funds that would tighten its grip on power and, in effect, preserve its nuclear ambitions over the long run, because as long as the regime exists, so do those ambitions.
In truth, the current deal is to a large degree a gift to Iran, one that effectively announces that the regime will, in the future, possess the means and the openings to continue developing weapons of mass destruction.
In other words, the deal is bad not only because it keeps the regime in power, but because it leaves in the regime's hands those 11 tons of unenriched uranium, which can still be enriched.
When you deal with the devil, there is no good deal.
And this, I think, is the point Trump fails to grasp. He is the more optimistic sort. He genuinely believes one can negotiate with murderous terrorists, and there is something pragmatic, even intellectual, in that belief. But when the governing doctrine is the Hudaybiyyah agreement, sign accords while you are weak, then break them once you have grown strong, which is the very essence of Muslim political doctrine toward the unbelievers, that optimism is misplaced.
The most one can hope for is that the next American president will understand this. But I have my doubts — because even this great president, in the end, grew weary.