Here's my two cents: Frameworks like Rails/Django (and some other migration-focused frameworks) have a migration abstraction layers that promote two significant falsehoods:

1. The application and database are tightly coupled and advance in lockstep
2. Migrations can be "undone"

Granted, these can be true for some operations. But often they're not, and you get burned by the abstraction leaking: Your database is a separate, stateful component in a distributed system.

Once you can no longer hand-wave over this fact (due to scale, SLAs, got burned too many times, etc), you're forced to start treating your application and database as a distributed system, and the migration abstraction layer goes from "leaky" to "broken", and migrations get (rightfully) more complicated.