As far as I can tell, somewhere in March 2021, our ScoreDirectorFactoryFactory code no longer looks at ScoreDirectorFactoryConfig.kieBaseConfigurationProperties.

I haven't verified this actually. If it's true, this is a regression.

Proposal A) Fix the regression
Proposal B) Fix the regression, but mark it as deprecated
Proposal C) Fail fast if people use it and mark it as deprecated. Does this break BC? Not really, we broke BC when we released this regression.
Proposal D) Outright remove it now. Breaks BC.
Proposal E) Status quo. Do as if we people can tweak the kie base configuration but they actually can't. That's misleading people. => VETO on E).