"In relation to maintaining referential integrity because there is no coupling to the domain there really is only one area of the code that needs to worry about this"
What can this passage possibly mean? If there's no coupling to the domain then what is the data doing there in the first place? The problem domain will enforce some kind of invariants on your data, which the schema will need to enforce either explicitly ( through database level constraints such as PRIMARY KEY, NOT NULL etc. ), or implicitly through application logic.
If you're trying to say that there's no relationship between different collections then your application is a much better candidate for NoSQL, but in my experience such cases are actually exceedingly rare.
"We reap other benefits from this approach, including a elegant security model which means we have fine grained access controls over what fields and documents are visible to users based on an access control policy."
The same thing can be implemented at the database level through views and roles in most SQL implementations, which tend to be much more robust than application logic in my experience. That's just my two cents on the matter, however. Security and access control in Mongo has always been pretty much abysmal.
"Trying to author your own aggregations is folly. In our application we have been able to do complex data transformations easily by having easy to configure transforms which generate the aggregations. Doing it by hand would be a living nightmare."
Why would I choose to use a database solution where writing aggregate queries by hand is 'folly', when I can easily pick ones where it isn't?
For a challenge, see how few lines you can write a MongoDB query in that finds all documents where an arbitrary date falls between the range of two date fields.
"Ten years ago I was where you are now; SQL was the light and the truth. Today my view is broader and I have been given good reason to question the accepted orthodoxy"
Ignoring the obvious passive-aggression here, I have worked with MongoDB for years. I'm not some stuffy SQL shill who will never budge. I have worked with both for years, both writing new applications and maintaining legacy ones. I have already "questioned the accepted orthodoxy", and come to my own conclusions.
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