There was no other choice. Nothing has been lost. Why making such a big deal out of of nothing. Zarif and the group knew Iran doesn't need to test more nuclear capable missiles or its warhead (That is the ICBM type) but has to invest in more precision and software and associated hardware. Like better optical recognition, terrain hugging methods ... So this deal if it secures funding and technology transfer for the rest of the work which is essential is overall a good thing.
Why do you think IRGC and Army was firing all these salvos of Shehab, Sejil ... not to know how it works. They already knew. It was to project power. They need not to do it now! It is over. The next phase has started and that is building ourselves financially and technically. Fateh-110 type is not a nuclear capable missile. Khalij Fars is not one. Expanding tactical missiles and improving its CEP by itself takes a generation if not at least 5 to 10 years. It is the best thing to do that and if despite all prediction an idiot attacks in the next 15 years then all this is nulled and nothing is lost.
Modeling IMU's, solving better navigation equations, including optical and terrain info. Expanding the software, building better MIRVs, Building better engines and miniaturising them all need money and time. They bought the country 5 to 15 years of time to do all that and more. The focus is now on peaceful Iran so I like to see what happens to any aggressor internationally if it goes against Iran militarily for now. Meanwhile the hard power is intact and it only will grow as the economy and soft power and knowhow grows. You sometimes have to dig in and take a breadth. We were running out of breadth with all happening around.
Next good thing that will happen is Houthis losing Eden and Iran saving face and persuading Houthis to accept ceasefire and release itself officially form that chaos. (anyway SA has made a big enemy there which Iran doesn't need to keep it inflamed) Then either regime will invest multiple times in Syria or come into conclusion to settle the faith of it by saving a portion of Baath party and removing Asad and going for an election in a schedule plan 1 year from now. In any case the gamble in Syria has no end as the economical power of the alliance is more powerful than the axis (Iran, Syria, Hezbollah and may be Russia). In any case once a major victory is achieved Iran needs to give in and accept a diplomatic solution. I think that is what Ghasem Soleimani was referring 2 weeks ago.
Anyway, what I am saying is that the deal is an opportunity Iran took it wisely. In the last minute US put pressure on Iran to accept some more terms and give more ground and they had to otherwise US would walk away. But overall it is still good for Iran. On e has to look 5 years from now. The power is to be safe but when diplomacy achieves it with fraction of the cost we should be happy. 5 years from now Iran is more powerful for sure and I don't think except ISIS fight there would be another one coming if all goes well.