[taffer]

> VCS for stored procedures and views is usually non existent

This is a mindset problem, not a technology problem. Treat your stored procedures/functions/views like code, not like data. Keep a separate "code" schema, put your procedures/functions/views definitions in files, and store your files in Git, just like Java or Ruby code. Deployment then becomes an automated drop and recreate of the code schema in a single transaction with zero downtime.

> Deploying application logic alongside these systems is very painful

This is not my experience at all. The stored procedures form an API. If changing the API breaks your application, you are doing something fundamentally wrong. API versioning should only be necessary if third parties depend on your API, but I wouldn't recommend giving third parties direct access to the database anyway.

> Once you have complex enough stored procedures, modifying the data changes things in unexpected or unintended ways

I assume you mean triggers because stored procedures don't happen as side effects, you have to call them explicitly. Regarding triggers, I agree with everything you say.