WordPress has long followed an operational model that makes deploying, updating, and maintaining it automatically difficult.
While the formal Twelve-Factor App structure adheres a little too rigidly to the Heroku deployment model, it offers a number of advancements that would greatly aid operational concerns with ClassicPress.
For reference, I'm referring to this: https://12factor.net/
As an example, implementation of configuration in the environment - not on the filesystem - would improve flexibility and make operating ClassicPress in a Docker container more viable. An excellent library for this exists in the form of Vance Lucas's phpdotenv: https://github.com/vlucas/phpdotenv
Another part of the Twelve-Factor App model that would help in operations is logging. WordPress's logging model is just to rely on the reverse proxy serving it. ClassicPress would benefit from adopting Jordi Boggiano's monolog library (https://github.com/Seldaek/monolog), as it implements the PSR-3 standard and makes logging much more manageable from an operations standpoint.
Note: this petition has huge scope, and would be best served by being adopted as an overarching strategy, rather than an atomic change.