Filippo Noseda published the article Privacy versus transparency: it’s time to look at the data on the data regarding FATCA and CRS.
In a projection made by the US Congress in 2010 it was supposed FATCA will bring in $8.6bn in additional revenue over the next decade (2010-2020). This has not come true, Noseda writes. On CRS:

There is no independently verified data concerning the success ratio of the CRS, but if the statistics released by TIGTA in relation to FATCA are anything to go by, it stands to reason that most of the accounts belong to compliant taxpayers. The OECD claims that voluntary disclosure programmes, offshore tax investigations and related measures have helped identify close to €126 billion in additional revenues so far. However, this could not be independently verified.

He comments that it is clear that FATCA has done damage:

What is clear, however, is that FATCA and the CRS significantly increased the level, complexity and costs of compliance borne by compliant citizens with bank accounts overseas. With FATCA, data show that this has led a number of banks to discriminate against US citizens, leading to account closures and the denial of service.

He is worried about confidentiality and data security and argues that transparency (through e.g. FATCA) may serve legitimate objectives, but needs to be proportionate. The proportionality and legitimacy of FATCA and CBT is an issue that needs better assessment, Noseda argues.

He ends with:

Nobody should evade tax. However, compliant citizens have a legitimate expectation to have their personal data protected against unnecessary intrusion from government authorities, especially in circumstances where the data show that they are unable to protect such data from unauthorized access, hacking and data theft.