The manual loading policy is deliberate.

Patchwork is first and foremost a testing tool, and tests often reside in the same codebase as the system-under-test. Add the fact that Patchwork slows things down considerably, and now we have a problem: we have to selectively enable Patchwork during testing only, or else we default to negatively impacting the production performance.

But let me know if you have an decent solution for the latter :)

I assume you will add a dev-dependency on Patchwork in Composer if you only want Patchwork during tests.

Since changing this behavior will have unexpected results for integrations that do manual loading, I would propose a (minor) version increment.