I'm not using Moo(se) but this looks like you are changing the interface after reload.

Obviously (for me) you must respect the contract, when replacing code in a live system.

Regarding data, there is a reason why languages like Haskell require their functions to be "pure", i.e. to have no side effects or inner states.

Regarding Perl modules, a reload would need to handle not only functions, but also with package variables being used outside the module and/or lexical closure variables carrying state.

I could think of a solution with a proxy module shadowing all this, but this l also depends on the concrete requirements.

And practicality is different for development and production scenarios..

Last but not least, I can't really comment on OO frameworks. If their inner workings make it impossible to make data persistent, there is not much which can be done.